Wow, thanks for that one, Vivkins3, I'd never have thought of anything like that! I've just found a 'Ta' river in Virginia, USA on the t'interweb. (I did wonder whether there was a Scottish dance called Glen (for valley) something but I couldn't find anything online!)
Thanks skinnymalink - I think you could be right about 'strathspey' - I have now learnt from a quick search of t'interweb that 'Strath' is a Scottish name for a river and of course there is the River Spey.
(I should have remembered that Mrs Braid's Guide Dogs quizzes usually need a bit of local Scots knowledge for one or two clues!)