It would be a bumper off job, then unbolt the headlight and any leveling attachments and connectors - at a guess 1.5 hours to remove then refit everything
Others who have removed xenon headlights may correct me on the complexity and timings
Assuming its raining and I take a break for a cup of tea
Joking apart removing bumper fitting the new light and a lot of fiddling to realign the light and bumper to get all the gaps correct and then aligning the beam is easily a 2 hour job DIY or perhaps an hour for a good dealer tech.
I'm assuming the lens is a clear indicator in which case the eBay estimate is reasonable given a pair will easily achieve £600. Long wait to find one though. New are around £650 and swap ballast, bulb, etc across.