John Lewis are currently offering a 3 year guarantee as standard over their normal 2 year guarantee on all iPad models.
This essentially covers everything except accidental damage.
This applies online and in John Lewis stores.
Prices vary according to iPad model. Mini starts at £269, iPad 2 is £319. and the retina display model starts at £399. John Lewis do price match other retail stores. (I believe the 2 is on price match as its RRP is £329)
3 year guarantee included at no extra cost. Ends 26th August 2013.