Currently there are no restrictions or extra paperwork for British tourist to enter Spain. By the end of 2022, however, you may have to apply for an ETIAS visa waiver before you enter Spain: this is a simple online application that will allow you to enter the Schengen Area with minimal hassle and paperwork.
If you own a property in Spain you might want to spend more than a few weeks in Spain and this is when you need to keep an eye on the calendar as you are limited to a maximum stay of 89 days. The law states; if you spend less than 90 days in Spain over the course of 6 months then you will not be impacted by entrance or exit visa requirements and you can continue to enjoy your holidays as you always have right now. Note that this applies for all of Europe and not only Spain.
The answer to your question; can British holiday home owners still live part time in Spain is yes, they can. But they are limited to 2 x 90 days within a year. So basically, you can stay 3 months in Spain and then need to spend 3 months in the UK and then you can come back to Spain for another 3 months stay.
If you want to stay more than the 180 days per year in Spain you have to apply for residency in Spain. You can find the details about residency in a separate article >>
It’s worth noting that, whether you live in Spain or are just visiting for a short trip, you will need to have at least 6 months validity remaining on your passport in order to enter Spain.