My CX5 is displaying a BSM fault on the dash related to a bump on the rear driver side bumper. This has been repaired however we have been told by Mazda that it has affected the rear sensors, lane assist and that I need a replacement unit costing £1.5K! Is there an alternative fix?
Any guidance would be really appreciated, thanks.

 

Welcome to the forum.

If you want the lane assist to work correctly you will need a new sensor.
The part (KB8C-67-Y30R) price varies from $650 to $1000 (US dollars) depending on the vendor.
Then add labor.
2017-2025 Mazda CX-5 Blind Spot Radar KB8C-67-Y30R | OEM Parts Online

 

I am looking for a UK part if possible

 

The part number KB8C-67-Y30R is OEM and the same in every country.
Just use your UK browser to do a search for a part in the UK.
Though buying in the UK doesn't mean you'll get the best price.