Upvote:4
You have a UK passport due to expire in 5 1/2 months and are travelling to a country where 6 months validity is required. At the time of your arrival, your passport will have 5 months remaining until expiry.
There is a very slim discretionary zone in Kuwait for entering without a valid passport as they define it. They might forgive a day or so if you are arriving from a 3rd country which did not have a facility for you to renew your passport, but arriving from the UK simply doesn't work. The bottom line is to renew your passport using one of the premium services, even the one-day premium if need be.
The alternative is to find yourself facing detention and removal; and having to contact the Foreign Office for local support. The Foreign Office will be able to help arrange a return flight and assure that your detention conditions are acceptable, but they will not issue a new passport to help you enter the country. The UK will bounce a Kuwaiti who arrives without a valid expiry term, and the Kuwaitis have every right to reciprocate.