What is the best solution to buy for mould on walls in the home?

Dehumidifier

Dilute bleach with water and use a spray bottle.

I’ve had better luck with a mix of 50/50 water and vinegar. Put in a spray bottle and spray the area. The vinager will kill the spores that spread the mold.

To get rid of the mold, use white vinegar. To help prevent it from coming back, it's a good idea to invest in a dehumidifier.

It took a bit....but yes it’s all gone from my place. Mold needs to eat....wet paper, old food...and it prefers dark. Deprive it of its needs. Daylight spectrum light bulbs, no moisture run a dehumidifier and zap it with the acid of vinager. The vinager kills the spores bleach won’t kill them...it’s been 3 years now on no more mold.

i haven’t seen the mold back In the 4 yrs I’ve been in the house.

probably a very good idea to seek the expertise of a professional