I have only been able to fit unit I am 80 years of age and I have just had a new Knee fitted and I had to wait for a short dry period to fit new unit as it is very difficult to get someone to do it for you for less than around £100. I have managed to fit the unit and it is now working. I live in a area with many trees I now feel a lot safer with my security lights back working. It is a pity that there are no organisations around that can help OAPs like myself who do not require a £100 before they will start the work. I suppose that's my fault to live to 80..