Putting cooker more than 300mm from sink

[plumbersandgasengineershelp]

If you or your DP is one, I'd be so grateful for a quick answer to this. The boiler is above the gas hob and the plumber/gas engineer has turned off the boiler, so no heat/hot water. I know it's not brilliant, but the cooker has been there for years. It's probably a major risk, which I do not want. The washing machine which is next to the sink could be swapped with the cooker. This would mean the cooker is next to the sink unit, cooker to the left, new sink unit to the right of it, with the drainer next to the cooker, sink much more than 300mm away from the cooker. New sink drainer does not go over washing machine, sits perfectly on the unit beneath. Sink is to the right, against the wall, draining board to the left, so keeping cooker away from actual sink.

I'd like to know if this is illegal. One gas engineer plumber told me it was fine, one told me it was illegal because the cooker would be too close to the sink, although the drainer would be between cooker and sink. Advisory, not law?

I'm not quite clear what the question is. If it's about the boiler being above the hob, you need at least 760mm clear above the hob surface to the bottom of anything that overhangs. You also need 460mm to anything within 50mm horizontally that's combustible. The 300mm is the recommended manoeuvring space for pan handles etc.
However the manufacturers instructions override all that. Have you got a make and model? Although I doubt any would allow a boiler close above.

Cooker in front of window isn't advisable either - those curtains would be alight in no time ! Cooker needs relocating on other wall... it's time for an overhaul I think !

Sorry - probably not what you want to hear !