Try to get pre-approved for a mortgage before you start looking at properties, this way you have a set price to work with. Casamona can recommend someone who will help you do this for free.
If you can buy your Spanish holiday home outright, do it. You will own the property outright without increasing your debt. If you don’t have the funds, there are two ways to pay for your foreign home. You can extend your main mortgage or you can get a new mortgage for the property. Extending your loan is currently a cheap way of borrowing the extra cash you need. The other option is to take out a second mortgage on your holiday home.