Now for the happy ending. Once I spotted the whole account number snafu, my mum went into the bank today to do the transfer.
I checked online that it had debited my RBS account today then looked in UBS just for something to do and it's showing on there already!

It says a 'booking date' of the 28th, Tuesday, so I guess it's not yet cleared funds. Doesn't matter.
Oh, and no men in suits showed up at my door (yet!). Thanks for all the information about limits, etc. I was a very nervous monkey for a while there.