Triton Shower Tower - Poor Pressure

[CF]

I had a Triton Unichrome Shower Panel fitted last Friday. I have an Unvented Cylinder Hot Water System which I had fitted 2 months ago, primarily to give me high pressure for my showers. I have an existing shower in the en-suite (a 20 year old Mira 88 Mixer) which supplies extremely high pressure showers (in fact I cannot turn it on full blast as it is too much). The Triton was fitted in my Bathroom but provides a hugely disappointing low pressure water delivery, especially in comparison to the normal mixer shower. Would the triton Panel have a restriction on the pressure or is it possible that the set up on the cylinder is incorrect? My Plumber, who also fitted the Cylinder is baffled by this. The Gauge on the Cylinder reads 3.4 Bar and there have been no other appliances on whilst using the Shower.
Any advice much appreciated.