Okay I'm a little confused...
Been to three garages, one being a fiat/alfa specialist. All told me the slave cylinder is inside the bell housing so it was a gearbox off job to replace and therefore to get the clutch done at the same time. (one even told me its an engine out job to do - but refused to do the work saying they don't touch Alfas...)
It's booked in with Beechdale Alfa tomorrow morning for them to take a look and quote me to fix. But I'm expecting them to be expensive to say the least.
Meanwhile the clutch has returned to normal, so I'm not sure they'll be able to spot a problem.
I'm wondering if it's worth me ordering the slave cylinder (which is from what I can see the most likely cause) from shop4parts for £35.90, and asking a garage to fit it for me. See how I get on from there.
What would be a reasonable amount for a garage to charge for labour on this? (I was quoted £30 for a full break/clutch fluid change, so I'm thinking £100 all in at worst?