A: Check that the hose is not kinked or collapsed internally thus reducing flow, easy way to check is to remove from shower and run without and see if shower behaves, also check that there is significant difference in flow when temp control is turned from hot to cold. If there isn`t then it is most likely to be thestabiliser valve which is now obsolete.
Our recommended replacement is the Triton T80xr Pumped shower which can be ordered online by clicking on the link below.

http://www.showerdoc.com/shower-spares/triton/ZTRITO-SP9008SI-Triton-T90XR---8-5KW-(White-Chrome)
Answered 43 days ago | Alastair