In reply to Pete.T:
If you can spare the time, don't do it as a day trip. The slog through the forestry commission bit will wear you down and detract from the route.
We walked in and did the long HVD up the cigar-shaped buttress, then bivvied in the cattle shed.
Next day did Fionn and walked out in time for dinner at the pub. Magnificent.
As for the route, it's gorgeous. I think 5a is a bit generous - if you are a confident VS leader you'll have no issues. The traverse isn't so scary and has loads of gear.
Go to it and enjoy it!
J