personally I think the labour cost are rather low that have been discussed so far, fair enough if 'mates rates' are in play, but I would expect around £350 labour plus the cost of the clutch kit for a 75 and LUK is around the £130 mark. so circa £500 for the job all in feels about right
you are looking at around 4 to 5 hours to remove the box, change the clutch and refit, most garages charge labour at around the £70 to £80 per hour and if they are cheaper then they simply take longer to do the job (if you get my drift)
I can do a clutch change in about a day and a half on an A2, on my own without a 2 post lift