Lighthouse:
I forgot to add, and is probably the main point really, you are confusing Cold Cranking Amp rating with the Ampere Hour rating.
CCA maybe 600A (according to the DaveK) but that is the maximum amperage it can provide for 30s at 0F before dropping to 7.2V. It is only relevant for starting and not for constant loads.
The Ampere Hour rating will be a lot less and is the actual capacity rating for a constant load. For example mine is an upgraded Bosch S5 with 110Ah capacity (CCA 920 I think). That still doesn't mean it can provide 110A for 1 hour due to Peukert's Law. There should be a rating on there to say xxAh @ xxhr and that is the only rating you can rely on unless you know the Peukert coefficient for that particular battery and work it out but again it will vary according to other factors.

DaveK:
If you have the chance just charge it up as much as possible and let it do the rest on the journey. Check your alternator output as well with a meter if possible, it could be it's not outputting enough, it should be over 13.5V tested on the battery with engine running. You also might have other parasitic drains but you need to start from a blank canvas and just charge the battery up fully and go from there.
Just so you know I was in a similar situation, I bought mine from a dealer and ended up with a battery light on which was a failed alternator. As I bought it basically as trade sale and got it for a very good price I wasn't too bothered but I appreciate your frustration.
I would look at yours this way, if that's the only thing wrong with it you're doing better than most
Congrats on your purchase

With jump packs and a completely dead battery you need to attach it and leave it on there for 5-10 minutes before trying to start it. It gives the dead battery a chance to charge off the jump pack so lessening the load when starting, you'll find it will then start OK.
There is nothing magically about start/jump packs, they are just batteries and leads. You just need to find one with the largest rated decent battery inside and still manageable to lug about. I have a Ring one that works fine and has a 17Ah rated sealed Pb battery inside, I wouldn't go less than that for a Range Rover. Lithium Ion packs might also be worth looking at as their technology is designed for providing high current in short bursts.

That's a good call re the alternator

The 2007 TDV8's are fairly well documented for alternator failure.....

Thanks for the jump pack tip, didn't know that. Most of us just tend to stick them on and try and fire up.

http://www.fullfatrr.com/forum/topic16178.html

Or just have a charged spare battery knocking about with a set of jump leads.

I have a 100ah Bosch s5 in the garage and a set of chunky jump leads to start ours and neighbours cars if and when needed. There is nothing that can't be fixed with a hammer😜😜
FFRR 4.4 SDV8 Autobiography Santorini Black.
KIA E-Niro 4+
2021 Discovery 5 D300 MHEV commercial

Sounds very similar to my booster pack

Plugs straight in to my leads - so guaranteed a top quality connection

Alistair wrote:

http://www.fullfatrr.com/forum/topic16178.html

Sorry

Just a personal view but I wouldn't bother with a Bosch S5. Had one and never felt it really warranted the premium. Ended that one by dropping it and cracking it.

Replaced it with, I think, a Yuasa or Varta or something, was silver, and felt it turned over much better and was about half the price. Replaced the Defender one recently with a Varta from a local Mann Batt dealer and again was cheaper than the Bosch. Ed

I think that Varta make the Bosch batteries too.

Not sure about yuasa though I noticed Halfords were selling them in place of the Bosch ones now. There is nothing that can't be fixed with a hammer😜😜
FFRR 4.4 SDV8 Autobiography Santorini Black.
KIA E-Niro 4+
2021 Discovery 5 D300 MHEV commercial

Yeah I saw that which makes me think it wasn't them as I don't think they were stocked in normal stores. Came from a local tractor place (proper tractors because this was Wales not Chelsea ). Ed

Most Bosch S5’s I’ve seen have failed quickly... I wouldn’t bother using one!