What's wrong with my fridge?

[muggo]

I'm in the UK & have an 11 year old Hotpoint Future fridge & the back of it keeps freezing food.
The seals are good, the temp setting is "normal", I don't add hot food to chill in it & don't open it more than necessary ie I've checked the basics & haven't found the solution. There seems to be more heat coming from the back of it than I've noticed before, but is that because it's warmer weather?
It's drawing 90w which seems high to me. With the cost of electricity, this is an issue if there are alternatives that don't use as much power.
I don't mind buying a new fridge if this one has reached the end of its life, but has it? It's the standard 600x600x850mm size & I'd like a wider one but can't find one.
In summary:
1 How do I fix the freezing issue?
2 Will a new energy efficient fridge pay for itself?
3 Can anyone recommend a fridge that's 650-750mm wide?

Many thanks in anticipation.

PS my 11 year old Hotpoint Future freezer is quite noisy. Is this an issue? Again, it's the standard 600x600x850mm size & I'd like a wider one if possible.
Any suggestions please?

 

[mattylad]

To answer no2:
No, it will not pay for itself - however a newer more efficient one may cost you less to run.

Yes it may run more in the heat as it has to work harder to maintain the temperature it is set to.

If you do decide to replace it can I suggest that you offer the old one on your local Facebook or Freegle reuse groups.