Could anyone recommend a specialist who could sort out my poorly engine for me? I strongly suspect it's a head gasket failure as the cooling system seems to be pressurising and when i bleed off the gas it smells exactly like exhaust fumes

The engine is a 2.1DJ. So looking for someone with plenty of experience of this engine. Honest, Reliable etc. Any recommendations would be greatly appreciated thanks! I'm in Doncaster South Yorkshire.
Mark.