sorry to here that the car is sick
first thing is reading your post they done all the diag over the phone and told you it would cost £1000 sounds strange to me.
can they change oil and filter over the phone to :-) as mine needs a service soon
back to the point
first of all you need to get it plugged in to a diag tool/code reader, find out what is wrong get the code or codes.
you may have a couple of faults not related ie you need the modified cam chain tensioner installed, and a you have bad sensor may be.
my advice for what its worth :-) if you are a member of the AA, RAC or similar call them out, tell them you EML light is on and the book says not to drive it, they will come look at it.
get a list of the codes :-) then you know where you are it could be something silly as a £2 part you never know.
post the codes and they guys here can help and give you advice
only place i trust is 1320 give them a call they are very help full. only thing is its about 90 ish miles away from derby but i would not go anywhere else, its about the same distance for me Contact Us
hope this helps all the best