Thanks for your email and help.Some clarifications:
Yes, I have paid for itunes match. I have only a few songs on my ipad. The majority of them are on my PC which is where I manage my itunes accoiunt from. My ipad streams songs on demand from itunes match.
Yes, I have also paid for extra space in icloud backup storage - I have bought the additional 10 GB
My ipad is a 64 GB ipad 3 device, UK model. NB I have upgraded it to IOS6. Therefore settings/general/usage/icloud-manage storage does not exist as a valid string. However under settings/icloud/storage & backup/ total storage it shows 15 GB and under available it shows 9.9GB
Under settings / general / capacity it shopwes 57.2 gb and under available it shows 19.1 GB
I do have some large photos and videos on the device. Is this likely to be the issue?
Thaks to all for your help.
Richard