@Jakee *********
depending on how often/how many times you're intending to enter and exit Thailand, the Multiple Entry Tourist Visa that
@Graham *****
mentioned might be your best option to avoid being questioned by Thai Immigration about why you (might) be entering so often, but, as UK passport holder, you can just arrive at a Thai Airport and be stamped in free on the "Visa Exempt" scheme. That doesn't have any fees attached to it as a Tourist Visa does & no applying in advance.