The price does sound reasonable as you would i take it have been a new customer signing up when you got it.
The best thing to do is wait until your current deal runs out and call retentions only they can offer you anything and will want to re-contract you,i recently got a very good deal free installation of my TiVo,moved my current V+ into another room,no activation fee and a further £7 a month off my bundle i am now paying less then i was before i had TiVo, but i had to re-contract for another 12 months to get it.
Ring 150 from your VM phone option thinking of leaving us to speak with retentions uk call centre.