I'm undecided about the 1p, but the 2p is utterly pointless and should go. Ditto the 10p, which is no smaller than 2x 5ps, so why bother? The £2 coin is also a bit daft - it's only marginally smaller than 2 pounds coins.
Perhaps to replace them we should have a £5 coin. The notes are always really tatty, but a coin would stay in circulation much longer, and it would be nice to have a "beer token" coin again [Yes, I live in London]
So, my coin currency would be 1p, 5p, 20p, 50p, £1, £5 and notes thereafter. Replaces our current 8 coins (1,2,5,10,20,50,100,200) with just 6 (good for vending machines and cashiers), improves circulation life of £5 and still allows values denominated in pennies to be settled in cash.
In fact, do we even need a 50p? Maybe make the 20p a 25p and ditch the 50p.