Bathroom Wall mount Heater Installation

Hi there,

Looking for suggestions, my bathrroms always seems to freezeing as no heat radiator were installed when bought.

Only electrical supply is currently being used in bathrooms:

Bathroom 1:
for a ceiling light,
mirror light,
Electric Shower point with pulling thread on ceiling

Bathroom 2:
for a ceiling light and
A button on wall just above to bathroom door to turn on/off exast fan

I found Electric Bathroom Heater Wall Mounted
https://www.thegascompany.ie/iopen24/electric-bathroom-heater-wall-mounted-dimplex-fx20v-maximum-output-with-free-next-delivery-eire-p-968686.html#.V8bdwtJTHcs

I'm not sure if this would be best solution.
If this is the right one, any suggestion / advice if its easy to install myself or do I need a electrician to install.

Thanks,