Can I fix my fridge freezer myself?

Hello all, I have a Hotpoint ffa91p Fridge Freezer. Had it for about 6 years now with no problem until recently.

First off I had a build up of ice at the bottom of the freezer. this I remove and checked the outlet pipe which I have ensured is clear and cleaned drip tray. (thanks to advice on here) since then about a week I seem to have lost all chilling...

The compressor seems to makes its usual vibrating noise but the fridge and freezer just dont seem to be chilling anymore. I have defrosted behind theback panal inside the fridge freezer (as a part of the pipe clean mentioned earlier) other than that I havent fiddled with anything.

It still makes that weird typical freeezer noises but it doesnt seem like the fans are spinning. It just isnt getting cold.

Any advice would be appreciated....thanks

Alex