Olie3146

Is this what I was looking for? 

"To do a hard reset disconnect the battery earth lead and hold the lead on the battery positive post for ten seconds.
When you reconnect the earth lead do so cleanly, don't dither." 

13 minutes ago, Jaguar Owners Club said:

Hi Oliver....welcome to the Club

It sounds like it is the main battery charge memory.....e.g, you have replaced the battery but the electronic memory is still reading as low.
You will need to reset the vehicle electronic memory to accept the new battery voltage (believe there is some info on how to do this on here).

This should at least get it to turn over.
If it does not start from there then this may be the reason it has not been running for a period of time

Let us know how it all goes

Thank you for the reply, I'll have a look and find out about resetting the vehicle memory 👍

I'll report and let you know how I get on 

So long story short : 

Purchased a 2010 Jaguar XF luxury on 58k miles as a non runner, been sat for better part of 3 years (no other information) 

When I got the car it's was dead, no life, so took the battery off an put another I had hanging around that had decent charge. All the lights came on, display asked me to insert smart key which I did, dash lit up and the display came on, tried to start and it just clicked, one single little click and then the screen goes off. 

So I did the following :

1. Changed battery in key fob and it works every press of the button now but no change in starting the car.

2. Used code reader, no faults currently stored but the above codes were in the 'pending' sections, from what I can see the first 4 relate to the maf and the last one is loss of communication with VDC.

3. Noticed that when I tried to start again it came up on the dash with "battery low, please start car or entertainment system with shut off in 3 minutes" or something to that effect (I've put the main battery on charge, but the second battery I thought had good charge on it)

4. Tried to take a video of the noise it makes on attempted startup, if you put the volume up you should be able to hear.

Thank you for any additional help