Cold water flowing back into hot feed.

[Askey]

Hi, I'd be grateful for some advice please. Every 12- 18 months I have a problem with cold water flowing back into the hot water feed through a shower mixer cartridge, causing all hot water feeds to run tepid or cold. Replacing the mixer cartridge fixes the problem, but only for a while.

Would a better solution be to have a water pressure regulator installed to reduce the pressure of the mains cold water? Are there any negative aspects to having a pressure regulator installed?
Many thanks in advance