What chemicals are available to remove and prevent mold appearing through brickwork

First find out whether it is mold or not. What you do next depends on this.

Assuming it is mold you need to do two things.

1. Clean it off - disinfectant/bleach solution should do the job.

2. Find out why it's forming. This is the important bit as if you just do the first step it will come back.

The usual cause is condensation which in a bathroom means you have insufficient ventilation.

So the ultimate cure is to fit an extractor fan above the bath to remove the steam. You can get ones that wire up to the light circuit and then "run on" after the light is switched off to provide additional ventilation.

Once you've done this redecorate.

The pink stuff is a bacterial biofilm. Cleaning agents containing bleach work well to kill the stuff.