Having similar problem myself but with different circumstances. House is 23 years old, bought from new, and boiler is the original Ideal Classic. Works fine and is serviced every year. Now on a fixed income so looking at reducing costs, so thought aha!! new boiler. The original is bound to be inefficient compared to the new ones. So had one guy round and it appears that all new Worcester Bosch boiler flues must have at least 600mm clearance from other flues and obstructions. Any seals/weld/joins in the flue pipe must be accessable to be inspected so that would mean re-routing my flue completly or cut big holes in my walls. The only problem is to re-route it would probably mean another 2-3000,(conservative estimate there), on top. So in all about 5-5500. How long to recoup that money in gas saving? New laws and regulations sometimes don’t make life easy. Got another couple coming round to see what advice they can offer. I shall wait and see.
