Heating costs in Spain are vastly lower than in the UK, especially if you rely on solar for a high proportion of your water heating needs.
Electricity can also be generated in Spain easily from solar (photovoltaic) panels and can easily produce 50-60% of your total needs. Try that in the UK.
Obviously, if you live in an urbanization overhead is very different if you live in a rural location. We have a substantial property in a rural area, and estimate our running costs are roughly 1/3rd of the cost in the UK.
Yeah, right. So many people have solar panels in Spain… I have not seen any.
Then Spain has a high cost for air-conditioning too, it is never needed in UK.
To live in a rural area in Spain is not something than anybody can do. Living in a rural area of any country reduces the cost by at least half (but then one needs to give up a lot of everyday life neccesities…).