Yes, Euan has it - it is indeed Loch Beoraid. Why it appears a Allt a Choire on Google maps is a mystery to me
The River Meoble flows from Beoriad down to Loch Morar and is (approximately) 20 times longer than the River Morar.
Loch Morar is the deepest stretch of freshwater in the UK, hence Morag (Nessies cousin) got in the deep there.
Awesome, all yours Euan
H