Shower pumps are generally noisy, the CT75 twin offer 2.1bar of pressure and works at around 64.1dB, there are quieter alternatives around the 50dB range, such as the one here, but they are double the prince (in excess of £200).
Your best bet would be to go to somewhere like your nearest plumb centre explain your looking for a quiet twin pump which closed pressure of 2.1 bar or more and see what they have in stock.
Other things to consider are how you can reduce some of the vibration noise from the pump, the video here explains about the use of a vibration mats, such as the one here.
I haven't heard from you in the last day or so, please let me know if you need any further assistance, if not I would appreciate if you could rate the service received.
That is correct, it looks like the one here, and normally located right next to your hot water cylinder.
I haven't heard back from you, please let me know if you need any further assistance, if not I would appreciate if you could rate the service received.
Please let me know if you have any further follow up questions.