Roca In tank Meridian Toilet leaking into bowl

[cluelesswithplumbing]

Hello

I've searched online and can't find the answer to this one. The toilet is a Roca 'In Tank Meridian' floor mounted one, which has been leaking for a while. A plumber from the water company came but wasn't able to fix as not a standard loo. Does anyone know if it is relatively easy to do for another plumber?

Many thanks

 

[Deleted member 120897]

It should be ok for anyone who has worked on them before, or who has access to the instructions/Roca technical help.