Faulty on /off switch on Triton t80i?

I replaced a faulty on/off switch on the triton t80i only 18 months ago but ther switch now only works if you hold it down manually .( a bit difficult to shower with one hand holding the switch in and the other...you get the idea..)
The switch seems worn or the contact is and the switch no longer makes contact . Should I replace the switch yet again or cut my losses and install a new shower . It is ancient after all.
Any ideas on the price of a budget shower?