Thanks for the replies, the fault was diagnosed as a blown spark plug which apparently had been cross threaded when it was fitted and as a result, the head has had to be skimmed again.
It also seems that when the main dealer did the initial work following the cambelt failure, they say that they did not remove all the spark plugs when the heads were skimmed (?!?!) and only removed and replaced the Nr.1 spark plug and 'conveniently', it is the Nr.2 spark plug that blew.
A little background history - I should say that I asked and it was agreed that when carrying out the cambelt rebuild, that they also carry out a 'full' service. According to the Alfa Romeo Service book (since new, the car has only ever been serviced by this particular main dealer) spark plugs should be replaced at 60,000 and in the service book, the car had done 51,000 miles at the 60,000 mile interval and at the point that the cambelt failed and the service was done, the car had done 63,500 miles but they have failed to replace the plugs.
The reason given for not replacing them at the 63,500 service was because the plugs cost £254 to replace and they were already doing the rebuild at a 'discounted' rate!
Earlier this week, for some reason unbeknown to me, I decided to look at the engine and having done so, I am now concerned that the front head may never even been off the block! There seem to be new bolts on the rear head and as I am no mechanic, could even be looking at the wrong part of the engine but, if I have paid for 12 intake valves and 12 exhaust valves I'm guessing that 'all' the valves have been changed. However, there are bolt heads visible on the front part of the engine block, that I'm guessing are to secure the head to the block and apart from one, which appears to have been attacked with a hacksaw, the heads of the bolts are all rusted and I would say that they have never been removed since originally fitted.
Fortunately for me, I have the car back but have not yet been physically presented (only told verbally) with the bill and I could even be doing the main dealer a huge disservice (hence my reason for not naming them) but I am left with several questions...
1. I am under the impression that all the spark plugs need to be removed, to allow the heads to be skimmed, is this assumption correct? According to the dealer, not so, as the plug sits in a combustion chamber but if the head is removed then seated upside down to be machined, won't the plug heads be damaged?
2. When skimming, are both mating services skimmed?
3. The garage claim that on the second occasion, the heads were skimmed on-site, is there such a thing as a mobile skimming service?
4. Is 12 Inlet and 12 exhaust valves a full set of valves for the 24v V6 engine?
5. Where would the Nr.1 and Nr.2 spark plugs be located? Are they in fact in the same head?
6. Are a set of 6 spark plugs really going to cost £254?
7. What visible (if any) damage would a blown spark plug create?
8. Finally can anyone recommend an Alfa specialist close to Wellingborough that I could approach to a second opinion?
I have no issue with paying for the work, if it has been carried out but I do have serious reservations about the Dealer, non more so than the fact that their customer service is awful and have only ever phoned me twice and one of those calls was to confirm how much I now owe them!
Many thanks for any guidance that is offered.
Oh, as for the squeal, it seems to be coming (intermittently and usually after driving for approximately 10 miles but not always so
) from the rear, is definitely a "round and round" squeal, as opposed to an "up and down" squeak, so assume it will either be a wheel bearing or a brake issue