My understanding is that there is no regulation on passport validity for entry to UK.
Non-EU passport holders require an entry visa which requires 6 month passport validity only upon application and issue of visa.
Emma's passport validity to Phils is not a problem either for immigration or airline carrier.
However Steve, please do check about passport validity issues for any countries you may be visiting as "stopover" either on the outward or return legs where you will be passing through immigration. Many countries do require 6 months validity.
