With £2 coins, some are worth much more than face value, but largely most are literally face.
The ones you want to look for are
* Single metal "Claim of Rights"
* Commonwealth games (2002) England
* Commonwealth games (2002) Northern Ireland
* Olympic handover 2008
A few others - error coins Royal Navy - Cat on the mast and Full flag error are the main contenders, pretty much everything else is £2 unless it's in uncirculated condition.
I will now be hung at dawn as this is clearly Post Decimal