How easy it is depends on the present layout and position of soil drain.
None of it is particularly difficult, Boto, but it is quite time-consuming. Waste pipes and hot and cold supplies would all have to be altered.
Then there's the new shower valve to fit; plus the shower tray and screen. Also, the 100mm soil pipe for the WC is usually the hardest to re-route. A lot of the plumbing would have to be boxed-in as well.
Then there's all the tiling...... and maybe some electrics.
The short answer is... yes, you need a price from someone.