Wow, thanks everyone for all these great responses! This is probably much better than whatever Pooleys has to say on the matter and is a great example of how useful PPRuNe can be. I found the strip on Google Earth so I can see the hazards that you have all described.
I'm keen to get some short/soft field landing experience, which is what prompted me to consider Bute. I've just had a look at the performance charts and with temperatures of 5-10°, no wind and MTOW, I'm within limits with a little to spare, so with a good short field technique, a bit of headwind and more conservative fuel uplift I'm good to go on paper. However, I think I'll tackle the longer and more straightforward Glenforsa first before I graduate onto Bute.