Hi Gem
Sounds like your fusebox probably got wet at some point

its really common as mk1's tend to leak a bit when they get old

kind of like an incontinent grandad

£50 labour doesn't sound too bad, theres loads of wires that they'll need to trace etc... they'll certainly earn it

Don't bother with a vag fusebox, you can pick them up for about £40 new from places like volkspares/eurocarparts etc... i've never had any problems with them - expect to replace a few relays though!!!
I'd strongly advise checking for any leaks before anyone touches the fusebox or it will probably just break again

been there done that

The most common places are:-
Loose, damaged or missing grommets on the bulkhead behind the engine - also look out for holes drilled for stereo's etc...
Through the scuttle panel, that bit under the bonnet behind where the wiper motor is
Rotten floorplan

was any of your welding in that area

Sunroof drainage tubes either blocked or dislodged - this is probably the hardest to fix

so lets hope its no that one
