Range from the cheapest fitting of a boiler magnetic filter £50 (Nat gas based in BR3) to the dearest fitting of a boiler magnetic filter £170 (J Williams based in BR3).
Comparing heating engineers estimates for fitting a magnetic filter gives you an idea of who will be better value but the best way to compare costs is to get actual quotes.
What to do - Get rates and quotes to connect a magnetic filter in br3 1 au by posting a job with HaMuch and we will send it to heating engineers in br3 1 au.

"Change the position of a magnetic filter"
SE6