Just to revisit this topic please:
The chimney/flue that accomodates the back-boiler also has a Baxi gas
fire, with access to the pilot light etc under it.

Now, is this fire an intergral fitting with the boiler or would I be
able to change this?

Having 2nd thoughts about taking the chimney out [in terms of actual
space generated and it's praticality] but we'd get at least 50% of
that depth back just by changing to a flat-panel type fire and
removing the surrounding fireplace etc.
BUT, if I do that as it stands, the pilot-light stuff would jut-
forward.
Any work-arounds?