I emailed them out of hours yesterday and received a reply with an appointment set for the date I specified (and also the time! mine is at 8.30am which is what I wanted).

I asked for a date in September and if that was not available for the next available appointment from that date.

Manila.ConsAppointment@fco.gov.uk

In addition to a UK CNI and two forms of identification, they have asked for a local CENOMAR so my partner is arranging that for me.