Help please!!! Does anyone know a mechanic in west london who can diagnose and fix my piaggio porter van problem?

Hi everyone,
My piaggio porter van (2008) broke down last week in Cornwall, and we had to be towed back to west london. Does anyone know a good mechanic based in west london, or even london, who knows about fixing piaggio porter vans?
Here are the symptoms.... loss of power, white smoke, really bad smell,
On the positive...what we do know is that the engine has NOT seized , and there's no oil in the coolant, or vice versa... which is all good.
Just need a mechanic with a passion and experience of porter vans please.
Thank you

It really isn't a very complicated vehicle. Any mechanic who is in any way qualified or experieced ought to be able to help you. But I don't know what options you have near you. Most of the outfits around here are happy to work on them.

The white smoke suggests water or coolant in the cylinders or exhaust. If it was straight after start up and there's a misfire, maybe the gasket is allowing coolant to leak a bit into one cylinder. But I'm not an expert, that's just a problem I had with mine.