Ok, so I got out in the HELD 2570's earlier. It was around 4C.
With them being thicker I got less feel for the controls, but it wasn't too much of a problem. The thickness also affected the heat getting through from my grips. It took a good 10 minutes and that was without too much clutch control.
I did a 20-25 minute journey and by the time I arrived I already felt my finger tips getting pretty cold.
I spoke to a guy in a bike store in Long Eaton that I just happend to be near and he said he wears them all winter. Though he sets out after having had them on the radiator etc. So it sounds like they might keep heat reasonably well, but aren't too good for warming up hands while on the move. Though I guess that's going to be the case for most winter solutions.
Not worth the £99.95 in my opinion anywho, so I'll be returning them
Heated gloves are great, I just hated having to wire up and plug in all the time. I like heated grips because they're always there and easy to turn on/off when required.
I think I'll try some gloves specifically designed to work with the grips next
