It's already been explained. This isn't a hand holding exercise.
Reducing your DHW gas bill by 75% is more than £40 saved.
Since it doesn't reduce your gas bill by 75%, that is irrelevant.
Are you perhaps complaining that I omitted "DHW" in this post?
By george I think he's got it!
No, he's just a bell end.
The Sunamp unit is sold by Intergas, who would have this pre-heat one of their combis.
https://theintergasshop.co.uk/sunam...-sunamppv-5-kwh-heat-batteries.html#More-Info
The Sunamp is sold by Intergas in their shop.
If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Are you a trade or supplier? You can create your listing free at DIYnot Local