Ok I joined my gym this year in march.

I'm happy with it, but when they gave me the talk before i joined they said you can freeze for monthly periods. Which would cost 10pound instead of the 36 pound.

SO i did this some time in august this year and all was fine.

I went there a few weeks ago wanting to freeze my membership for January and now they're telling me 'We don't do that anymore'

I told they guy I've already done it once blah blah blah, and he gave me a name to write to (a manager) to see if she'd allow it, but I presume he was talking about long term because he mentioned a doctors note and it being at her discretion.

Now I want to know if I have any rights to freezing my account? I was under the impression that I could do this when I first joined, 12 months maximum if I wanted to, and I didn't know it would be changeable.

In my contract it says they may change the price throughout the year, which they did, upped it a pound a month, but it doesn't say anything about stopping freezing an account. The excuse I gave them last time was time issues, and I will be having the same issue in January.

So what do you think I should do?
And what am I entitled to do?

It depends a lot on the terms of the contract you signed - certainly needs checking out - but it's worth warning that gyms are pretty notorious for building potential unfair terms into their contracts, not least automatic renewals. Worth checking the last out especially.