Thanks for the replies folks, now to find somewhere that will do a returns if not suitable type thing. I haven't found many places which do unfortunately.
If you're buying on the internet you're covered by Distance Selling Regs (DSRs). These give you rights to cancel a contract and return goods, and are in addition to The Sale of Goods Act (goods should be as described, fit for purpose and of satisfactory quality)
Under DSRs in most cases - buyers have the right to cancel (within 7 days) and return goods for any reason - doesn't fit, not suitable, change of mind etc...it doesn't have to be faulty.
There are some exceptions .... perishable goods and custom made items for instance.
You're entitled to a full refund which includes postage out, but you usually have to pay to return the goods.
Not all internet retailers make your rights to return under the DSRs clear, but it's usually there somewhere in the small print. Sometimes you need to remind them. Every now and then when returning something I still have to point out my right to a full refund including postage.
For more info -Office of Fair Trading