After my Ford Focus C-Max was returned from its annual service at my local branch of a major service centre, I noticed a slight intermittent rattling from the engine. Having returned the car three times for inspection, I was summoned to the forecourt to be told by the nervous centre manager that they’d wrecked the engine. Apparently, during the service a spark plug had been broken and shards of porcelain had entered the engine. I received profuse apologies, was told this was a very infrequent occurrence and assured that I would receive a brand new Ford supplied and fitted engine. I twice asked for confirmation in writing of this, but the following day before any written offer was made, my car was removed, without my permission, from the centre. When they finally made a written proposal it was very far from what I had been promised.

They are offering me a reconditioned engine, supplied and fitted by businesses of which I have never heard. Although my C-Max is six years old and has done 67,000 miles, it has never once let me down, requiring only regular services and replacement of consumables when necessary and I have all the documents to prove this. I feel that this offer is unacceptable because it is contrary to their original promise (doubtless made to avoid a nasty scene on the forecourt), the residual value of my car will be reduced to zero and the chances of continued, hitherto total, reliability will be unlikely. Please can you advise me of what I should reasonably expect in these circumstances and how I should proceed?