I don't have a GPS in the club aircraft (none installed) - or an autopilot. The aircraft does have an autopilot, but it's labelled U/S, as is the case with all the club a/c as far as I know.
And you think it perfectly acceptable to go bowling through some of the busiest airspace in the country with the minimal of equipment and experience?
Is the kit you actually have FM immune? How exactly are you navigating?