I cant really accept that someone would sign off a service without doing a TT.
What part of if you fiddle with combustion or gas TT before and after is confusing?
A TT Should always be done on any service and CP12.
If the Hob is burning crisp and there are no problem above or around it and the soundness test is fine and yeh I mean 0 drop never mind the allowed drop, you dont really want to be leaving any drop, its more work for you and most of northern gas networks confuse themselves with this I spent many time arguing the toss about this and find it funny they think your allowed 4mbr on pipework.
Anyhow for CP12 on hob I would agree with the british gas guy, how far do you go.
Its all about covering your bum, do what you feel you should do but for me, I would not expect to check pipework behind an electric oven, its a question of how far to do you go.
what if you find a 2mb drop do you put it down to the old appliances or start to cap and rule out pipework, it does not need to be done, but something happens and its on pipework and you signed it off as okay?
I would be more worried about that than little ECV or cooker hose on hob.
0 drop only screw the poor customers pocket money, they will be the ones claiming against you if it all goes bang, I find it insane that this regulation still stands.
If your do really want to start removing ovens ect.. make sure you finish your purge after your TT, wash them greasy hands and think about signing off any drop.