There are flights from Madrid to UK and i believe also Barcelona to UK these have been flying regularly into Heathrow i think, so if you really want to, you can go Alicante to, for example, Madrid, into Heathrow (you'd have to check this, but I think its Heathrow ) and then on to your uk destination from there, i suppose it depends how much you want to get back,its not direct but its still a way back