2004 v6 freelander auto

Hello, I have come across an odd issue with my freelander this week, it was used all week driving approx 100 miles a mixture of road and light dirt tracks. The following morning on start up all that happened was a loud clicking noise followed by the display flashing rapidly and and a F4. It doesn’t allow the engine to even attempt to crank and the longer you keep trying to turn it over the weaker the clicking gets. Battery is good, I’ve checked as much of the wiring as possible and all seems ok, in the end I got a code reader test completed and it threw up 4 codes , 2 we managed to clear and the dash cleared of the F4 code but after attempting to start 2 reoccurred.
C1551 - can gearbox data failure
C1221 - brake pedal switch electrical fault.

would either of there’s completely stop the freelander from even getting close to trying to fire ? How could a drive one day fine and and the next a dead truck? Only work carried out in last 3 weeks where front pads renewal and tires changes. 4x4 still works fine and freelander has only had a new starter motor in the last 4 years since I’ve owned it with only 80,000. It doesn’t help that I’ll need to tow it to a garage if I need them to have a look.
Has anyone got any ideas what I need to try and look at and what these fault codes actually relate to? I’m hoping it’s a cheap easy fix with lockdown, any help and support massively appreciated

Rapid clacking or clicking is normally from the starter. It's caused by not enough power in the system, normally a faulty or discharged battery.
I'd be checking the the battery connections and earth cables, as it's potentially one of those.

Thanks for your reply. Do you think these codes are just from a power supply issue and hence why it’s in limp F4 mode. I’ll test the battery today, the earths are difficult to find on the v6 auto as it’s so compact but will have a go. I did had jump leads using my wife’s car on the battery and it still didn’t start, with ignitions on radio and lights work fine so guess the battery has enough juice .just dead with clicking and dash flicking. I’m a bit of a novice so appreciate your help.
Anything else I should try before I call a mechanic

The engine earth strap is difficult to find on the V6. However you could add another, linking the chassis rail under the battery tray (there should be a suitable M8 tapped hole available there), to the top of the gearbox, next to the gear position sensor (again M8 hole iirc). This will give an additional earthing point, which would eliminate any future earthing issues.