Hi Robin which eldoLED drivers are you using they seem to come up between 50 and 70 £ each on google. Also with the MR 16 spots is it 1 channel per spot or can you connect them in series.
Duncans idea of DMX cv drvier > SSR > 240v seems quite elegant. But from all the rest of the Loxone kit the relay extention is one of their more affordable units. Which relays did you use ?
SRS lighting dmx relays coming in at around £15 per channel. They have NO / NC variants.
PXM.pl have a lot of nice dmx gear including dimmers but no idea on pricing. Made in Eu (poland) so hopefully should be quality gear.
KNX ... I was surprised but the actuators are not that expensive. Haven't looks at ETS yet .
TheBen do a nice 240v dimmer too £50 per channel range.
Have not looked into the KNX stuff much yet but these were just the things that popped up.