Well my O2 order has updated on the website from 'In Process' to 'Complete', and I'm also able to go into the Tariff Management bit and remove the data bolt-on, although I haven't actually tried yet.
I know the quidco money should be fine if I remove it, but is it worth the risk...
Edit: Just tried to remove it and it's pending, will be done on 02nd May apparently.
Not smart to alter the contract with quidco pending