Eligible with British passport for 144-hour visa with 3 months remaining on passport?

David, if your itinerary is:

London - Guangzhou - Cebu

And you don't have any additional stop of any kind, especially within mainland China, you are definitely eligible for 144 hour visa free transit.

You will just print out your flight tickets and have those printouts with you. Also, it is highly recommended to have at least the first overnight in Guangzhou booked in advance and to have a printout of this booking too. You will declare at check-in in London that you will travel to Cebu, Philippines via Guangzhou using 144 hour visa free transit. After a short inspection of your tickets, you will be allowed to board the plane.

Upon landing in Guangzhou, you will approach 144 hour visa free transit counter where you will fill out the blue form and shortly after you will receive a sticker in your passport. Everything is free of charge. You will clear the immigration and you are free to enjoy your time within the entire Guangdong province.

As far as your passport is concerned it is important that it is valid for at least 3 months on a day of your arrival in China. So, having "just over 3 months left" is perfectly acceptable.

Thank you so much for your clear explanation, it's a big relief to hear that because you never know!

I'm hoping to get free accommodation for the first 48 hours with China Southern Airlines since they provide a service for that and then print out that booking too.

Thanks again.

This is also fine. If China Southern provides you with free accommodation, this is the best option, of course :) You should just print out their confirmations. I have done exactly the same a couple of days ago, but I have a layover of only 12 hours in Guangzhou. Never mind... China Southern is one of few airlines providing this service.