Sorry it's been a long time before you got any response, I hadn't seen this post come up on my "unreads" until now.
I've only had experience of solid fuel Rayburns, I'm afraid. If you haven't had the appliance serviced for a while it is probably worth getting it serviced though, by someone experienced with them. We had a service for the very old solid fuel one in a cottage we moved into, spent a few £hundred (included new fire bricks), but it gave the old girl a whole new lease of life! And at last she could warm the whole downstairs, the upstairs radiator, and cook dinner as well
. (It was only a wee one.)