I'm a newcomer to Alfas but here's my thoughts.
1. Drivers Seat: Seat completely collapsed the other day and I am going to have to get a new seat.
- Sounds like a new seat is in order - cheap as chips off ebay.
2. Exhaust: There is a hole in the Exhaust I am unsure where the hole is or how much it will cost to fix
- Get underneath and find out. Either replace or if not too bad a hole then exhaust putty, some clamps and the outside of a bean tin will fix it if you're desperate! Don't laugh, it worked on my Metro when I was a student 15 years ago, enough to get through the MOT.
3. Windscreen Washers: Just not working.. No idea why.
- Pump may be gone? I take it there's no noise made?
4. Passengers Door: Attempted to open it the other day... heard a loud noise and now its just not working at all. when trying to open from the inside or out.
- Sorry difficult to say without seeing it and having a poke around.
My advice would be to ring Duncan and leave a message to get back to you - he's busy and if you've been down there you'll understand why - he's a one man band. I'd never been to him before, left a message around lunchtime, and got a return call at the end of the day. When I went down there to get mine looked at and spent a few hours there I saw why. He'll pick up your message and give you a call back when he isn't running round like a blue arsed fly! I'd definitely recommend him though - even more so if you're on a budget