On a FL1 TD4 it can be done without taking too much apart but it is VERY fiddly.
See this post
https://www.landyzone.co.uk/land-rover/how-to-change-turbo-on-a-td4.221780/#post-2510752
I think I paid £ 200 for a replacement turbo (exchange unit) 3 years ago and it took me and a mechanic mate about 6-7 hours to do. That does include cleaning out oil from intercooler etc. and plenty of tea and fags whilst doing the head scratching bit - at some points you are working blind.
It can be done much quicker though. 45 mins has been claimed but i think that is removal only and probably pushing it.
So if you are not doing it yourself then base your best guess on £ 250 for the unit and 5-6 hours labour charge start to finish. I guess you're looking at £ 500 give or take.
If you are doing it yourself then £ 250 and a weekend working on the car.