sure, you have central locking i take it on the key? delock it.. debadge it, maybe smooth the tailgate completely n remove the rear wiper?. get yaself down to halfords n get some filler, fibreglass, primer, sanding paper (p80, p180 and p320 for filler work) (p800 wetordry for your primer).
ive delocked my doors n debadged the tailgate without welding any plates. for the doors ive sika-flexed metal plates (bout 1 mil thick) on the inside, then fibreglassed the outside and fillered to smooth it off.
for ya tailgate jus get some fibreglass n put it on the inside so the hole is covered. then when its hard, rub down the outside with some p80 n put a skim of filler over it. sand it down til your happy.
as for prepping the car you can literally prep it a million different ways. each garage prefers different methods. you could grey scotchbrite the hole vehicle so the paints faded. you could go over the lot of it with some p400 sanding paper (possibly p320).. or you could get ya bucket of soapy water n prep it all with P800 wetordry sandpaper.
i should start selling diy guides with bodywork
hope that helped, anythin else? jus ask
FM