Surely be easier to swap from the XS BL to a 525SL with the schnabel forend? I know it's not a London style, but it's a lot thinner than the trap forend. Having the forend of the XS BL reworked will likely kill its resale value.
The stock balance weights available to fit the XS BL will fit in the 525SL with minor fettling.
I went the opposite way, the schnabel forend was too small for my gorilla sized hands, so swapped to the XS Pro. If Browning sold a trap style forend for the 525SL, chances are I'd still be shooting it.
Shame Browning haven't offered different forend options for both these models. They've got the forend blanks in both black and grey laminate, and the tooling to make both. As they're both laminate, matching shades and patterns of wood isn't even an issue like it would be for walnut. Guess it's because if you could buy a 525SL trap forend, would there be a market for the XS BL?