Welcome to the forum Carlo. You should also be aware that it is mandatory to get pictures of your car on here too and as quickly as possible ....
I'm based in Buckinghamshire and I can recommend L&M International in Lane End near High Wycombe (independent and low labour rates) or SGT in Taplow (dealer). I've not use them for a while but AlfaAid in Maidenhead also get a strong thumbs-up from the Alfisti here (another specialist, but high labour rates).
I do most of my own work on my 1998 model myself, having tackled brakes, suspension and some of the electrics. In a attempt to help others, I started to put together a series of "how-to" documents and stored them on a website ... you can click on the link in my signature area below ...
Many of the regular maintenance jobs are pretty straight forward, but like all cars, if they have been a bit neglected, they tend to be a bit stubborn and won't let you get bolts off, etc. without a fight
Good luck!