Hi I own JD Winter Ltd we are based in Consett but cover Alnwick to Middlesbrough. I am not allowed to tell you prices on the forum (site rules) but to swap a combi to an ATAG A325EC (best boiler out there) would be around the £1900 mark incl new controls and a magnetic filter. A Baxi Duo Tec would be around the £1600-1700 mark. The prices could be less if the install is straight forward. Our website is www.consettplumber.com if you want to see some examples of ATAG's or google ATAG and check there website out. Hope that helps! Thanks James