further to Pm and in answer to statement spouse gets all. see flow chart about who inherits what when there is no will under \uk rules
http://www.tollers.co.uk/system/docs/178/original/Rules%20of%20Intestacy%20Flowchart.pdf
http://costacalida.angloinfo.com/af/275/costa-calida-lawyers-law-firms-and-legal-advice.html
Shirley Fisher Camposol Business Centre is a UK commisioner of oath. You could make a declaration to her on oath that you are sole benefiiciary
as a Building Society Manager i would often requests next of kin to provide this especialyy if UK estate was not liable to obtain a Grant of Probate - maybe this would be accepted by Spanish lawyer