The '6 month rule' that's often quoted is a bit of a myth anyway. The vast majority of countries that British tourists visit have never had such a rule. It's only a small minority that have but lazy travel agents, rather than learn and explain the different rules for each country, have often just told travellers that they 'must' have 6 months validity on their passports in order to be able to travel.
Things might change in respect of travel to EU countries though after the Brexit transition period has been completed but there still seem to be some doubts over the matter. So you need to check the rules for the particular country that you're planning on travelling to in May of next year. (For example, if you're hoping to travel to the USA, you DON'T need 6 months validity on your passport. Most visitors to the USA do but there's an exemption for holders of UK passports).