It is true that most RGI technicians will know what the fault is and how to repair it at a fair and sensible price.
But not all of them will charge a fair or sensible price if they see an opportunity to make a bit of extra profit due to the customers lack of knowledge.
Of course one should not give any advice of HOW to do gas repairs but there is no reason at all why one cannot give a price guide for an RGI technician to supply and fit a gas control valve.
There are people who will rip off their vulnerable and / or un-informed customers. Helping such customers to avoid being ripped off is not giving DIY advice on gas work.
Bernard,
Many thanks for your reply. That was all I was actually looking for.
I can get the parts at cost plus 5% so it kind of makes a difference knowing which part is needed.
If I was located in Bedford you would be receiving a call.
Once again thank you.