Can you tell me what type of tied accommodation you live in please. Are you taxed on an accommodatiion benefit?
Take a look at the notes here and here.
If it was your intention to live in the property at some point, at least until you decided to sell it, you can nominate it as your main residence and pay no CGT. You would normally have to do that within two years of haiving more than one home. The cost of your property for CGT purposes is either the value when you inherited it or what you paid the council for it if you bought it from them.
I hope this helps but let me know if you have any further questions.