R107 1989 Woes - any advice
 

Got this back from the garage doing work on my car - already spent about 5k with them on various things and was expecting to pick it up last weekend:
I had it programmed to be cleaned for you this morning and the car would not start at all well with lumpy misfire. We fitted new distributor cap and rotor arm , spark plugs, HT leads and nothing improved the car. WE carried out a compression test and found three cylinders very low on compression indicating valve failure, this now will require the cylinder head to be removed and further work to be carried out.

And a quote for nearly £1500!!!!

Any advice?