Once you have liquidated the inheritance in England and have payed the taxes involved there, you will have an English title of property that will have to be validated in Spain- by a Notary- to get the spanish title to register that property under your names. You will have to do that before selling to a third party.
In terms of taxes: The inheritance taxes will be payable in England. Then the only plusvalia to consider in terms of yours and your brothers´non residents taxes declaration is the difference between the value of the property when you acquire it by inheritance and the value you are selling it for.
There are some projects for internationalization of inheritance and wills Law, but at the moment we need to do things as I have exposed.
Maria de Castro