Ferg, I think you got that right! My problem is I don't like to have anything controlled by my phone...so old-fashioned, I know, but it just doesn't feel right switching on CH etc from miles away.
However, I control my TV by phone or PC from Spain (streaming my home content free of charge) and my CCTV is similarly on an app...but i was "forced" into that for both of those because there is no other option since I had to let the maid go due to financial circumstances...
Anyway, I fitted the Sangamo unit with ease, but yes, programming it is causing me some problems simply due to the access. I will overcome this!
using manual override on the old timer I learned that all i need is about an hour of power in the early morning to provide enough hot water for my morning shower and some dishwashing during the day. The Sangamo has a half/one/two hour boost function so everything else is catered for, should I have guests, for example. I feel this will be more economical than having it running 24/7 and just "held" by the stat. I have turned the stat down from 60° to 50°, but it still is 60° at the taps. I should have addressed this ages ago, but being away for about 5 months of the year, i just didn't bother...it's only lockdown that caused me to investigate.
Just to summarise, the Sangamo unit is extremely neat, fits into a standard single back box, and also comes with a surface mount box if you need to use that method. It's very slim when fitted to a recessed box, and the only tiny modification I had to make was to flatten the top and bottom lugs on the back box to allow it to sit in properly. It has an earth terminal, albeit the whole back is plastic, and the terminals seem well made, indeed the whole unit is pretty well constructed with an extra layer of insulation between the gubbins and the outer case.
In my view, it is ideal for my purpose, it's just the programming that gets me, and I have always had a problem with menu-driven stuff...an age thing, i guess.
it's rated at 16A, rather than the 13A of many of the cheaper mechanical timers, but those are so much easier to programme if you just want the same on/off times every day. I don't need 5 on/off times per day, different times for each day, and a change at weekends. My neighbour's 12 year old nephew is coming round tomorrow, so I'll get him to sort the timings!
Next time, I'll go for one I can programme from my armchair...
Good shout, Ferg!