I was previously on 32GBpm for about £15pm (a rolling contract that I obtained through HotDeals UK) and contacted EE to see what the latest best deal was. Someone on this forum had previously posted they had managed to get 64GBpm for around I think £25pm.
The saleslady at EE said they couldn't offer this so I said fair enough, I will wait until another offer comes up. After a brief pause, the salesperson said hang on whilst I talk to my manager to see what I can do. She came back with an improved offer but nowhere near what I wanted. She then consulted her manager again and came back with what I have now, but on a 2 year contract only. I was OK with a contract as EE offer a good service and is the only 4g I can get where I live (no landline and no other mobile provider in the area).
Even though I have only been on this plan for about 6 months it appears I can upgrade again, should a better plan become available.