How to mend a Bristan 8-inch (200mm) traditional shower rose?

We have two "Bristan Trinity thermostatic surface-mounted showers with rigid riser and diverter to shower handset chrome-plated". They were installed by a previous owner (who left no paperwork) about six years ago, so out of guarantee. They provide a "rainforest-type" shower.
In both cases, the 8-inch shower rose (aka shower head) has failed. The perforated plate has dropped slightly on one side, causing the water partly to escape at the side of the plate.
I unscrewed the rose and then detached the plate with its bracket and rubber seal. The bracket consists of several struts which hold the plate in place. The top of the bracket (where the struts meet) fits into the rose casing and is screwed into a swivel joint which in turn is screwed into the shower arm extending from the wall. Each strut is rivetted at the base onto the plate. With each of the two roses, the rivets at the base of two or three struts had failed (popped out). In one case, a strut had fractured (metal fatigue?).
It is clear that the rivets have failed due to inadequate design to cope with the water pressure (we have a Monsoon 3.0 bar twin pump). I believe the rivets will fail after 5-6 years. No surprise then that the Bristan guarantee is 5 years!
Soldering is no good. I don't have welding skills or kit. I don't have a rivet gun and in any case a re-riveting job would probably damage the plate and ruin the water spray pattern.
I remonstrated with Bristan Customer Services, claimed design/manufacturing defects and threatened bad press but they did not budge. I had to fork out around 2 x £91 for two new roses (P&P incl, complete with swivel joint) - best buy-new deal I could find. I suppose I will be doing the same in 5-6 years! Or we ditch Bristan at some point, especially as we've had to replace cartridge seals and recalibrate the temperature control...
Anyone had a similar experience and how did you fix it?