The Yaesu FT-8100 in the car has now been replaced by an Icom E-2820 equipped with the D-Star digital voice mode and built in GPS positioning. This enables transmission of my current position every time I use the PTT when using a D-Star digital voice repeater. As far as I can see, there is no built in way to use the GPS data to transmit an analogue, packet style APRS burst in beacon mode. Using the D-Star GPS function in beacon mode is a bit of a no-no through the repeater network currently.
The local D-Star repeater on the Wirral is GB7WP, more detailed information can be found here.
With thanks to www.aprs.fi from where I have embedded the Google Map below. The map updates automatically but tests have show my position information is lagging real time by less than a minute.