the gas pipe needs to be in a timber boxing/ channel filled with fibreglass with a protective plate over it imo. Like you would have seen on the T vale type jobs.
you need to consider that a leak would fill the surrounding area to which electric cables/ switches are present. a flick of the switch and any explosive mixture will go bang.
you also need to consider the sleeving of the flue system? nail clips are designed to hold in foam lol.
whats the timber for on the side wall? looks like a planned kitchen cupboard in front of the boiler, the boiler would be better on the side wall the gas run surface on the plasterboard and a boxing under the boiler between boiler cupboard and worktop.
what builder is it paul? who 1st fixed it?