I feel I must speak up in support of British Gas here.

I've used them twice to replace CH boilers here in Oxfordshire. On both
occasions they gave the best price. Their staff were knowledgeable and
helpfull. The installers arrived on time and worked hard. All in all
they did a good job and I find it difficult to fault them.
When I told the fitter who replaced my own boiler that I was intending
to fit a gass range cooker, he oversized the gas pipe to allow for it
in future. Really good service.

Don't let a few bad cases spoil the whole large organisation. Like all
such companies, BG are only as good as their staff and these will vary
across the country. Of course, their good work rarely gets publicised.

John