Thanks for joining Chris.
Your request for help is appreciated, but it’s rather unusual insofar as requests for renovations are normally aimed at bodywork and body panel requirements.
My primary recommendation would be:- don’t entrust this mechanical ‘restoration’ to a ‘company’.
The car is now 21 years old, and loosely comes under the heading a ‘classic car’, so if I were in your situation, I would be looking up a local all-makes classic car club, and joining that. Members there should be able to come up with some local recommendations of who to go to, and more importantly - who not to go to.
Again, if it were mine, I would be getting that garage to give you a report on its mechanical condition, and highlight and prioritise a schedule of work necessary to bring it to an acceptable standard.
Perhaps you could let us know how you get on Chris.
Good luck and kind regards,
Gareth.