Thanks guys. Ho-hum!!!
I guess the WiFi access point is a bit of a no-no! I assume the 'client' mode is embedded in the WiFi chipset and no ad-hoc arrangement is possible.
The Antenna connector was a query as I guess the wavelength of the 2.4Ghz band is somewhere around 13cm so the internal would be about quarter wavelength at best and I don't suppose it is a folded dipole. With a full wavelength dipole, the ERP from the chipset would probably be sufficient to cover my premises (though whether the heating effect might be a problem in such a confined space). Even if were a runner!