Oh dear...there is.
So it seems that the device I bought, which claimed to be a "RTL-SDR RTL2832U R820T2 TCXO AM FM DSB USB" device is not what I thought it was :-(
20180904 183017.194 [main] INFO i.github.dsheirer.gui.SDRTrunk - ******************************************************************* [5MB/15MB 35%]
20180904 183017.241 [main] INFO i.github.dsheirer.gui.SDRTrunk - **** sdrtrunk: a trunked radio and digital decoding application *** [5MB/15MB 36%]
20180904 183017.241 [main] INFO i.github.dsheirer.gui.SDRTrunk - ******************************************************************* [5MB/15MB 36%]
20180904 183017.241 [main] INFO i.github.dsheirer.gui.SDRTrunk - Memory Logging Format: [Used/Allocated PercentUsed%] [5MB/15MB 36%]
20180904 183017.241 [main] INFO i.github.dsheirer.gui.SDRTrunk - Host CPU Cores: 4 [5MB/15MB 36%]
20180904 183017.241 [main] INFO i.github.dsheirer.gui.SDRTrunk - Host OS Name: Windows 10 [5MB/15MB 36%]
20180904 183017.241 [main] INFO i.github.dsheirer.gui.SDRTrunk - Host OS Arch: x86 [5MB/15MB 36%]
20180904 183017.241 [main] INFO i.github.dsheirer.gui.SDRTrunk - Host OS Version: 10.0 [5MB/15MB 36%]
20180904 183017.241 [main] INFO i.github.dsheirer.gui.SDRTrunk - Host Max Java Memory: 247 MB [5MB/15MB 36%]
20180904 183017.397 [main] INFO i.g.dsheirer.util.ThreadPool - Application thread pool created with [4] threads [5MB/15MB 36%]
20180904 183017.397 [main] INFO i.github.dsheirer.gui.SDRTrunk - Home path: C:\Users\Gavin\SDRTrunk [5MB/15MB 36%]
20180904 183017.412 [main] INFO i.g.d.p.SystemProperties - SystemProperties - loaded [C:\Users\Gavin\SDRTrunk\SDRTrunk.properties] [5MB/15MB 37%]
20180904 183017.412 [main] INFO i.g.d.p.SystemProperties - SystemProperties - application properties loaded [C:\Users\Gavin\SDRTrunk\SDRTrunk.properties] [5MB/15MB 37%]
20180904 183017.428 [main] INFO i.g.d.settings.SettingsManager - SettingsManager - loading settings file [C:\Users\Gavin\SDRTrunk\settings\settings.xml] [3MB/15MB 21%]
20180904 183017.881 [main] INFO i.g.d.s.mixer.MixerManager - loading system mixer devices
[LOADED] Output: Primary Sound Driver CHANNELS: [MONO, STEREO]
[LOADED] Output: Headphones (MINIJAMBOX by Jawbone Stereo) CHANNELS: [MONO, STEREO]
[LOADED] Output: DELL P2317H (Intel(R) Display Audio) CHANNELS: [MONO, STEREO]
[LOADED] Output: CABLE Input (VB-Audio Virtual Cable) CHANNELS: [MONO, STEREO]
[LOADED] Output: Speakers (High Definition Audio Device) CHANNELS: [MONO, STEREO]
[LOADED] Output: Headset (MINIJAMBOX by Jawbone Hands-Free) CHANNELS: [MONO, STEREO]
[LOADED] Input: Primary Sound Capture Driver CHANNELS: [LEFT, RIGHT, MONO]
[LOADED] Input: CABLE Output (VB-Audio Virtual CHANNELS: [LEFT, RIGHT, MONO]
[LOADED] Input: Headset (MINIJAMBOX by Jawbone CHANNELS: [LEFT, RIGHT, MONO]
[LOADED] Input: Microphone (High Definition Aud CHANNELS: [LEFT, RIGHT, MONO]
[8MB/15MB 52%]
20180904 183017.881 [main] INFO i.g.d.s.r.RecordingSourceManager - RecordingSourceManager - discovered [0] recording configurations [8MB/15MB 53%]
20180904 183018.184 [main] INFO i.g.d.s.tuner.TunerManager - LibUSB API Version: 16777474 [9MB/15MB 59%]
20180904 183018.200 [main] INFO i.g.d.s.tuner.TunerManager - LibUSB Version: 1.0.18.10866 [9MB/15MB 59%]
20180904 183018.231 [main] INFO i.g.d.s.tuner.TunerManager - discovered [12] attached USB devices [9MB/15MB 59%]
20180904 183018.231 [main] INFO i.g.d.s.tuner.TunerManager - usb device [8087:0024] NOT LOADED: Unknown Device [9MB/15MB 60%]
20180904 183018.527 [main] INFO i.g.d.s.tuner.TunerManager - usb device [0BDA:2832] NOT LOADED: SDRTRunk doesn't currently support RTL2832 Dongle with [RAFAELMICRO_R828D] tuner for tuner class[USB Tuner:RTL2832_VARIOUS Vendor:RTL2832 Device:SDR Address:0BDA:2832] [9MB/15MB 62%]
20180904 183018.527 [main] INFO i.g.d.s.tuner.TunerManager - usb device [0424:2744] NOT LOADED: Unknown Device [9MB/15MB 62%]
20180904 183018.527 [main] INFO i.g.d.s.tuner.TunerManager - usb device [8086:1C26] NOT LOADED: Unknown Device [9MB/15MB 62%]
20180904 183018.527 [main] INFO i.g.d.s.tuner.TunerManager - usb device [1033:0194] NOT LOADED: Unknown Device [9MB/15MB 62%]
20180904 183018.527 [main] INFO i.g.d.s.tuner.TunerManager - usb device [03F0:094A] NOT LOADED: Unknown Device [9MB/15MB 62%]
20180904 183018.527 [main] INFO i.g.d.s.tuner.TunerManager - usb device [1BCF:2880] NOT LOADED: Unknown Device [9MB/15MB 62%]
20180904 183018.527 [main] INFO i.g.d.s.tuner.TunerManager - usb device [8087:0024] NOT LOADED: Unknown Device [9MB/15MB 62%]
20180904 183018.527 [main] INFO i.g.d.s.tuner.TunerManager - usb device [0BDA:0138] NOT LOADED: Unknown Device [9MB/15MB 62%]
20180904 183018.527 [main] INFO i.g.d.s.tuner.TunerManager - usb device [8086:0189] NOT LOADED: Unknown Device [9MB/15MB 62%]
20180904 183018.527 [main] INFO i.g.d.s.tuner.TunerManager - usb device [8086:1C2D] NOT LOADED: Unknown Device [9MB/15MB 62%]
20180904 183018.527 [main] INFO i.g.d.s.tuner.TunerManager - usb device [0424:5744] NOT LOADED: Unknown Device [9MB/15MB 62%]
20180904 183019.513 [main] INFO i.g.dsheirer.icon.IconManager - loading icons file [C:\Users\Gavin\SDRTrunk\settings\icons.xml] [9MB/15MB 64%]
20180904 183019.747 [main] INFO i.g.d.playlist.PlaylistManager - Attempting to load version 2 playlist file [C:\Users\Gavin\SDRTrunk\playlist\playlist_v2.xml] [9MB/23MB 42%]
20180904 183019.747 [main] INFO i.g.d.playlist.PlaylistManager - PlaylistManager - playlist not found at [C:\Users\Gavin\SDRTrunk\playlist\playlist_v2.xml] [9MB/23MB 42%]
20180904 183019.747 [main] INFO i.github.dsheirer.gui.SDRTrunk - starting main application gui [9MB/23MB 42%]
20180904 183147.056 [AWT-EventQueue-0] DEBUG i.github.dsheirer.gui.SDRTrunk - Application shutdown started ... [17MB/40MB 44%]
20180904 183147.056 [AWT-EventQueue-0] DEBUG i.github.dsheirer.gui.SDRTrunk - Stopping channels ... [17MB/40MB 44%]
20180904 183147.056 [AWT-EventQueue-0] DEBUG i.g.d.c.c.ChannelProcessingManager - Stopping Channels ... [17MB/40MB 44%]
20180904 183147.056 [AWT-EventQueue-0] DEBUG i.github.dsheirer.gui.SDRTrunk - Stopping spectral display ... [17MB/40MB 44%]
20180904 183147.072 [AWT-EventQueue-0] DEBUG i.github.dsheirer.gui.SDRTrunk - Releasing tuners ... [17MB/40MB 44%]
20180904 183147.072 [AWT-EventQueue-0] INFO i.g.d.s.tuner.TunerManager - Releasing [0] tuner(s) ... [17MB/40MB 44%]
20180904 183147.072 [AWT-EventQueue-0] INFO i.g.d.s.tuner.TunerManager - Shutting down LibUsb ... [17MB/40MB 44%]
20180904 183147.072 [AWT-EventQueue-0] DEBUG i.github.dsheirer.gui.SDRTrunk - Shutdown complete. [17MB/40MB 44%]