Seems a reasonable deal to me. With The £60 Quidco cashback you'd effectively pay a fiver a month. I pay a tenner a month for Virgin's 300 + 300 plan. I use most of my text allowance each month but only about 3 minutes of calls.
Here's the website's blurb:-
"About this offer
Get loads more talk time. And loads more texts. All for a lot less than you'd usually pay on a 12 month price plan. It's a cracking deal - and the cost stays low for the full 12 months of your contract.
Just pop our SIM into your existing phone - and enjoy outstanding service from the word go. Our UK call centre helps with everything from tariffs to texting. There's free delivery when you buy online, and our 14-day returns policy guarantees you peace of mind. You can even keep your existing number."