RRUK does a key refurb service through the for sale section so may be worth sending it to him! I did mine myself and its fiddly, but from memory the battery is soldered to the circuit board so can be unsoldered and a new one soldered back in! Depends how handy you are or dare to be.
The keys that charge when in the ignition can be charged by sitting on an electric toothbrush charger apparently, well the bmw ones anyway. Not sure if that's worth a Google and try?

Well Miggit,

Let's make this easy......................

I'm a chef, one who cooks!
I used to live in Kenmore, little village in Perthshire!

Then I bought a computer and needed an email address...................

The rest is history ...............................................

Hahahahahahahahhahahahhahahahhahahahh
 2014 vogue se

All sorted guys,

RRUK is on the case  2014 vogue se

Great big thank you to Adam, RRUK for fixing my key!!
Lightening service!

Many many thanks

David 2014 vogue se

Only just seen this Ken, many thanks!  Discovery 4 HSE
1998 110 TUM HS FFR Hard Top XD WOLF
1982 Series 3 Hard Top

*Gone:L462 D5 HSE LUX, L663 Defender 110 HSE, Discovery 3 HSE, 2014MY Range Rover Sport 5.0 Supercharged AB Dynamic; L405 Exec Vogue SE 4.4, 5.0 Supercharged Autobiography, Defender TDCi XS CSW, Defender TD5 HT, Vogue SE TDV8, Vogue TD6, RRSport SC 4.2V8, Classic 3.9 Vogue Auto, Land Rover Series 3 SWB

Who's Ken??

Thanks David 2014 vogue se

LOL, its the Chef Ken More thing again, sorry David! Discovery 4 HSE
1998 110 TUM HS FFR Hard Top XD WOLF
1982 Series 3 Hard Top

*Gone:L462 D5 HSE LUX, L663 Defender 110 HSE, Discovery 3 HSE, 2014MY Range Rover Sport 5.0 Supercharged AB Dynamic; L405 Exec Vogue SE 4.4, 5.0 Supercharged Autobiography, Defender TDCi XS CSW, Defender TD5 HT, Vogue SE TDV8, Vogue TD6, RRSport SC 4.2V8, Classic 3.9 Vogue Auto, Land Rover Series 3 SWB