I can see why nobody has succeeded so far!

First off John ignore my comment above about number of wires. You only need + and - from the battery obviously to connect to the charge protection PCB which you take off your old SL battery.

The battery is OEM which means it's not available commercially only to companies to fit in their equipment. I spoke to Samsung in the UK who don't do batteries at all then their commercial offshoot in Holland called Pleomax that does BUT they said they don't do these ones and said try to call Samsung SDI in South Korea but they won't speak to you about just 1 or 2 batteries so I gave up at this point with Samsung.

One of the numbers on the battery PGF523759A does bring up a Palm battery available in France only (?) which looks similar and although it's 3.7V it's only 850mAh :-(

It is a 3.7V DC battery which is the standard mobile phone battery, according to two different electrical engineers I spoke to you can increase the mAh and as long as the Volts is kept the same it will not do any damage but will give more power obviously.

Batteries though, as I found out today, are not listed in size though and it's very hard trolling through them all to find ones that fit all the specs. The max I have found so far is 1500mAh which is not a great deal more for all the extra hassle.
i.e. attaching the circuit board from the old one to the new one if it has contacts not wires etc etc. The batteries above 1500mAh seem to increase in size! surprise surprise.
Standard Nevo SL battery is 1350mAh if you believe the SL spec sheet.
www.mynevo.com/images/uploaded_images/NevoSL_brochure.pdf

BUT (cop out for the moment I know) I have now found, by pure fluke, a supply of genuine Nevo SL batteries in England and will be picking up mine tomorrow, sorry I know, but I want my SL back up and running ASAP. The place is trade only but will sell to me as I am buying it through my company.

Battery cost is £67 + 15% VAT = £77.05 and does not include delivery or fitting either.

John I am in Surrey and work in Berks (not sure where you are) so if you can get your Nevo to me I am quite happy to get 2 batteries and fit yours as well!

I will keep looking but it has to be 2000mAh plus to make it worth while and so far no luck at the physical size we need :-)

TBC...