Not too bad a job but just take your time.
Nearside is easiest as you don't have the fun of disconnecting the fuel filler pipe and breather - the jubilee clips are likely to be corroded solid and might need cutting off, make sure you have replacements ready.
On both sides, be careful undoing the two bolts that secure the rear wing to the outer wheel arch - either the bolts will snap and/or you'll find the alloy is corroded and will fall to bits - you'll then need to fabricate new mountings. You're also likely to find a similar corrosion issue where the rear mudflap bracket bolts to the rear wing near the bottom of the wheel arch aperture.
Last area you need to watch is the pop rivets that hold the rear quarter panels to the goal posts.
Once you have removed the rear wings and quarters (yes it all has to come off) you'll need to separate the quarter from the wing - they are held inplace by a number of nuts and bolts - these might be seized, so use plenty of WD or similar lubricant and take your time. If you apply too much force you risk distorting the rear wing.
Re-fitting is simple enough, bolt new quarters to wings then fit wigs and line everything up and hen pop rivet quarters to goal posts, re-fit lights etc and job done! Would say a good mornings work, not difficult but a bit of a faff. Good luck.
BTW while the wings are off it would be a good idea to deal with any evidence of corroding alloy - using a wire brush remove all the loose, flaky and powdery stuff, spray with etch primer and then you can apply some stone chip or similar to help keep it at bay.