Many greetings from the Stornoway desert (really! we're on our 22nd consecutive day without any measureable precip here: It's a 1-in-30 year event)...
Now, you are correct... the Stornoway Airport record stretches back to 1942~ only, when it was opened during the war. Previously, thre have been at least 5 or 6 different sites, all around Stornoway town (some 2-3 miles inland). Infact, the site has even moved around the Airport at lot, from sandy frost hollows near the NATO buildings, to its current site on top of a dune.
It is all a bit of a detective story, and one for the homogenisation folks, but I'm getting there slowly- as it's one of longest continuous records in the UK (the records back to at least 1855 at Lews Castle). Unfortunately, most daily stuff before 1930 is undigitised... and contrary to popular mainland belief - Stornoway does has considerable local variation in climate in both precip and air temperature (see Graham, 2012)
All the best, Eddy
Ref: Graham, E., 2012. A Hebridean frost hollow made visible. Weather, 67(2), pp.45-47.