Thank you all, it's a stressful and shite situation really!

In the meeting I told them I'd never been told this and my manager (J who hates me) said 'yes when we spoke to you about X and Y last time') I said I don't recall anything being said- how can I argue with that!?!

With regards to business ideas- It's doing something which would place me in direct competition with my current company. I'm going to sit down the next few days and look at it in detail with a friend of mine who is a programmer and feels it could work.

Also I'm sure they'll give me a good reference as they wouldn't have given me the promotion and pay rise if they really thought I was shite.