Should I return this gift?...

Hannah
My dad has never been much involved in my life in any way other than financially as he works in London as a manager and makes a lot of money a year. So for him to buy me a £130 all singing all dancing baby swing (suitable for use up to 6 months) was not a huge surprise and will not have been a big purchase to him. However, what we really need is a cot mattress and as we don't have a lot of money and I don't think that such a fancy (and large) swing (we live in a very very small house so it would be in the way...) is a necessity whereas our daughter needs a mattress as soon as possible and if I were to return the swing, I would get £130 worth of Toys R Us vouchers which would be enough to buy a cot mattress as well as a more practical swing/bouncer and probably a few other little bits too...the more I think about it, the more tempted I am but I don't want to offend him...what would you do?