Servicing Access?? 1998 Hijet EFI Wheelchair Vehicle

Re-posted from the general board, sorry for the duplication;

I am about to service it but have run into a major problem..................... How do I get the plugs out? The airfilter was reasonable easy, but as I can't access the rear engine panel (due to the wheelchair loading ramp winch etc.) I'm stuck trying to get the plugs out via the access hatch under the passenger seat or from underneath; boy do I wish I had ramp or pit! I have the vehicle tool kit, including the plug spanner and if anybody can tell me how to ge the thing ON the plug I will be impressed. I'm not a mechanical inept having built, rebuilt and restored numeous vehicles over the years; even the Relaint Rialto I chopped up and turned into an off roader had better access than this!!

Any advice appreciated.