Thanks for your replies everyone .
Here's an outlier.
I have 40m reinforced pole hose connected to 60m if old microbore on my Claber hand reel. Light as a feather.
Why people use microbore let alone minibore is beyond me.
But then I don't use a pump controller either.
And I use an immersion heater for warmth.

How is the immersion heating fitted to your tank, is it a separate fitting or on the lid of the tank, got any pics or dealers that sell them?
Actually , no need , I’ve just looked at water heaters in a few websites, far too much money for me, 3 grand plus vat 😧
An immersion heater plus fittings is a couple of hundred quid. Should be fitted as close to the bottom of the tank as possible using a mechanical flange.
That sounds a much better price, have either of you got a picture of how they’ve been fitted ?
The reason I whinged about the ones for sale on a few suppliers, I’m not doing as much work now, after I had that fall just about 41/2 years ago ,and had to have half my left skull removed to stop the inside bleed . So during my off for sickness , a lot of customers got a new wc . Enough of that it’s been on before during my sickness , but’m back to work which I enjoy doing .
Youl be able to wire up and fit the imersion yourself if you can follow simple instructions it's pretty easy.
It's not hot by the time it comes out the hose though. If it's just repeat monthly cleans then there's no time difference between the 2. The hose is nice and warm though which does help more than anyone will ever know who doesn't clean windows and think a warm hose can't make much of a difference.
The electric meter is like a stop watch until it gets up to temp. Think it's about a tenner a night.
I think it could be cheaper running hot into the tank to start with. But a couple of pound you'd save isn't worth the your time to do it.
is that just hot water from the tank, or straight from your tap then filtering in the van?
Hot water does make a huge difference on maintenance cleans especially if they are costal with salt or bird poo and bee pollen and fly poo . Warm water is better than cold for cleaning but hot water is much better than warm water
Putting hot tap water through resin will kill it quite quickly so I have been told by ones that have done it
If working in places like that I suppose it would be useful. For the majority that won't be the case though. The windows aren't really dirty after 4 weeks unless there's been a storm. For they windows hot or cold isn't going to make them faster. As a normal 4 weekly wouldn't need much scrubbing so you wouldn't save anytime on the scrubbing side if it.
If you had a good few contracts that are 4 or 6 monthly I'd think it would be something worth getting too as I imagine itl shave a fair bit of them.
Where I am I don't think it would make it any quicker as the windows aren't really dirty. But for the people who work there? I've said before, 1 minute sounds like nothing, but if your in an area where the windows are always dirtier because of the location, then 1 minute added up through out the year saved on each house then its shouldn't be seen as an expense. It's a must have that will pay for itself after a couple of years by doing maybe 2 houses a day extra that you wouldn't be able to get done without it.
For people in that situation. It's a no brainer, I wouldn't even look at it as an outlay. I'd view it more as a saving that it's going to end up being in the long run.