HELLO Mick,
Pls. listen to us,be careful, guard your heart and your money. This may hurt you bcoz she's your wife and you love her but I think she's only after your money ( I hope I'm wrong though)There's no such thing as medical to apply for a spouse visa that's not a requirement at all. Your wife will only be called for an interview with the British Embassy if they are not contented with the documents you have submitted.
Okay let's make things clear for you , to appy for a spouse visa, you have to fill in the application form on their website, after filling up the form, you have to print it out and submit it to the application center in Makati PERSONALLY. Of course, you can never submit the application form if you don't have and meet all spouse visa requirements and haven't paid the visa fee yet.
I BELIEVE THAT YOUR WIFE HASN'T DONE ANY OF THE ABOVE STEPS YET THEREFORE SHE WILL NEVER NEED A MEDICAL CHECKUP NOR BE CALLED FOR AN INTERVIEW.