Bathroom sink with 50mm backed plasterboard question

[compact]

Hi

I'm insulating the exterior walls with plasterboard backed by 50mm insulation.
In the bathroom I'll be having a sink hanging off the wall i.e. no pedestal.

Is there any issue with the insulation?

i.e. the bolts bolding the sink on have to pass through the insulation before the brick, so might, over time want to bend?

 

[JBPHS]

Where basin is to be fixed, remove insulation and fit a piece of timber to same depth.

It's all about using your noggin

James.