2Q Mira Advance ATL, stopped working no lights electric, replacement making a noise is this ok?

I have the Mira Advance ATL flex as I have mobility issues. A few weeks ago it went beep and stopped working I think it said reset and it worked fine for about 3 weeks. A few days ago I went to get a shower. The electric was not working on the shower no lights or function. My husband checked the isolator switch and the fuse box no fuse went and everything seamed well with the electrics. My husband bought one to replace it as we have another upstairs and he did it before. only problem is it works fine but it is making a high pitch noise while the water is running like tinnitus not a mechanical type noise. I think it is slightly different it just says mira advance looks like standard is this why the noise? 1. Is some thing wrong with how he has put it in. Does he need to tighten something? He did do a little plumbing and electrics in the 70's and was an engineer but in New Zealand now he just does admin. He just put everything in the same place. 2. Ideally I would like to replace the parts of the faulty one its about 3 years old and we live in a soft water area. is there a group of parts that would ensure it will work again? I would like this as a spare as I have another shower the same upstairs which is a standard. Is the tube thing with hose by no 9 supposed to have water in it and if so how would you drain it. I know you fix them is it possible to give a approximate quote? I don't want to post as this will be expensive only to find I cannot afford to have it repaired. I may have to wait until March or April before I can afford it anyway as I am medically retired and our income is low. We spent everything we had to replace the shower and with Christmas and then the car insurance due it may be a couple of months before I buy the parts if that is a choice. If I get an idea of what is needed it will give me an idea of whether we need to throw away the shower or repair. sorry for the long story but I had two questions and this will help me make up my mind what to do. Thank you and have a lovely Christmas and new year.