You should get VAT advice, the Council can purchase the curtains, but they would have to place the order, the invoice would need to be in the councils name and the funds would have to come from the Council. You can then gift them but then it comes down to any benefits you might gain from donating the curtains, for example if you were then allowed to use them for free, that would be a benefit and reclaiming the VAT would be fraudulent. If you decided to give a grant, you don’t necessary have to use s.137 because that is the power of last resort, there are plenty of other powers you can use instead and there is one for the arts and entertainment.