E46 suspected engine failure - loud knocking

[b16a2_VTi]

Hi all,

I'm posting this on behalf a good friend of mine who's engine is little poorly.
I was in the car when this happened.

Under load in 5th gear the engine lost power we pulled over and we could hear a knocking noise.
The cars has around 150K and gets an oil change ahead of scheduled with the correct 10-60 spec (before any one asks)

He is based in Preston, but is more than happy to get the car transport outside of the north west to a garage.

Worst case scenario he may require a bottom end rebuild - Any recommendations? Ideally those who have had work carried out.

Thank you