Hi Said,
You are having silmilar problems to mine in the past. I had tough time with our dealer

As an advise, if you are rsbuilding the engine, use forged internals as you may decide to take it to higher power levels so you'll be ready. It might not be cheap option but will put your mind at rest. You need someone who knows what is he doing when building the Coupe engine.
You can try the "Parts for Sale" section as some forged parts offer pop. You can also check with Barbz as he is close to you (in UAE). I'll PM you his e-mail.
I'm sure other memebers will come along and advise sources in UK.
What's you plan for tuning? horspower?