It sounds that the Creda flow regulator or temp thermostat has failed in the electric shower, this type of fault would require a plumber to attend.
The replacement parts are likely to be around £30-50 depending if it is the thermostat or flow regulator.
Should you wish me to recommend a suitable plumber in your area please provide me with your postcode.
Dear Miss Mew, I would appreciate it, if you could please log back in and rate the service received, and let me know if I can be of any further assistance.
Hi Miss Mew, I havent heard back from you, if you have everything you need, please rate the service received using the star rating, so I can close the case.
Should you need any further assistance please advise how I can assist you further.