Help needed with my Freelander 2 TD4S 2008 7k miles.

The saga so far is as follows,

1. I get a tow bar and electrics installed by an auto electricians in 2008 and the local dealer charges me £50 to code them in. All success for 2 years and no faults with them or the reversing sensors.
2. The battery throws a cell and dies on me, 9 volts after an overnight charge. Never was very good. The dealer does not have a new one and suggests an independent supplier but helpfully says keep a live connection to the electrics as you change it to prevent and recoding issues.
3. New battery is fitted by me following live lead advice and using a motorcycle battery to supply a constant 12 volts. Everything works fine except the reversing sensors and the trailer lights that were fine right up to the flat battery saga.
4. Take the car to the dealer who says the electrics are not land rover approved although I know they are it is only the tow bar that is different and cannot reprogramme them in.
5. Dealer charges me £100 and says I need to have new electrics fitted and the invoice says that they have tried to reset the system although the trip mileage, range and fuel consumption are all the same as before it went in. A reset changes them all to zero.

I think the dealer is being less than honest so any thoughts would be welcome.

It doesn't sound right to me

I have got LR electrics, previously had battery off doing a reset, no problems with sensors after

Had battery changed, no reset needed to my knowledge

I guess your limited to dealers , is there a independent?

Of course it could be a coincidence Former Mod/Member, with the most post & Chicken George Arch nemesis

On my last F2 I had the battery off at least 3 times and replaced once and never had a problem with the electrics, I think they're telling you a good tale. I had LR assist out twice due to software glitches and on both occasions they fixed the car by taking the battery off for a couple of minutes and then reconnecting it and letting the system reboot itself.

Well thanks to those who replied as I have fixed the problem by disconnecting and reconnecting the battery.
It's all absolutly fine now. But as for the stealers well a little word in their shell like will be coming up.