I changed out the batteries between the other key job, and the same thing, any ideas?

 

A common problem is that the contacts within the fob need cleaning. Try a little alcohol on them.

 

See if this helps in the cleaning process.

Link JagRepair.com - Jaguar Repair Information Resource

 

Should I just clean where the four buttons click or the whole board?

 

I have just cleaned both sets of FOBS. Used a cotton bud with alcohol. Cleaned the contacts on the circuit board and in particular the inside of the rubber cover where the contacts fit into. They both now work immediately and upto about 6 metres from the car.
Rob Seignior, Australia, 1997 XK8 BRG coupe.