In article ,
Andy Hall writes:

I don't believe that it is a mandatory requirement for a CORGI
engineer to have one of these, but considering that they start at
about £200, there is no reason that somebody servicing boilers should
not have one.

It can't be mandatory -- I couldn't find a CORGI gas fitter who had one
when running through them in the Yellow Pages. I mentioned this to
Keston (having just fitted my Keston at the time), and the chap I was
speaking to agreed that they mostly didn't.

--
Andrew Gabriel