Axa do offer such a deal, but no guarantee it'll be any cheaper than you seeking two policies from different companies.
Definatly worth doing some phoning around as you're in a very different situation than you were last time you got a quote. Some of the specialist packages for women may provide cheaper quotes, so worth keeping the option of going with different companies.
Adding you to her car if you've a full NCB should have little to no increase on the policy (sometimes adding a spouse can reduce the quote) while adding your wife on a provisional with no NCB may or may not have an impact on yours (depending on company/age/etc.).