New Combi boiler

Other

I have an old boiler approx 20 years old. It has a recent gas safety certificate but I have to spend about £700 to replace a very long flue which is damaged.
I am thinking of replacing the boiler but I am worried about the new EPC regs that we might have to comply with.
This is a victorian house with new double glazing and the correct thickness loft insulation and when I had a new EPC about 2 years ago the rating was downgraded from a category C to a category D and the existing was said to have a good efficiency rating.

I am hoping that if I install a new combi boiler it would improve the EPC rating but I am not that hopeful.
Any advice about which combi boiler would be best (2 bed house) or would it be wise to just fix the flue and wait to see what this wonderful government are going to inflict upon us.
Many thanks
Mary