I have just purchased a 99 Discovery V8 Commercial manual, Just stripping the old girl out for a new headlining and other bits, now I am looking at putting a straight through exhaust from CATs back on the old girl, have searched eBay/Google for suppliers but just not getting anywhere apart from a centre box delete pipe, does anyone know of any suppliers I can contact? Also, the battery fitted is a 75AH which feels sluggish/slow to kick the old girl over, always thought it should have a 100 AH any advise also on this matter....Next one is a parts issue, the internal bulkhead is not with the vehicle, does anyone have one of these sale? Any help/pointers much appreciated.

Thank you.

Rimmer Bros supply stainless cat back system for your engine or did, the system won’t be straight through it will have baffle in the silencer/muffler. If the removing of a silencer will make more noise… it possibly fall the MOT.
I fitted a stainless Janspeed cat-back system 12 years ago and and it improves the engine response unfortunately Janspeed don’t seem to do anything thing for disco V8s now.

My disco V8 has been using a 069 or 072 battery for the the last 24+ years, and all were around 70/75 on its 4th battery now and never had any problems with battery, spins the engine over easy, 3 revs and it fires up a it should, then the alternator takes over. If not i’ll start thinking of a replacement.
The link below recommends 069 for you engine and all battery suppliers seem to have a ‘battery finder page.

Go to a breakers and cut your own bulkhead from a scrap D2 before it goes into the crusher

https://www.tayna.co.uk/car-batteri...bVbMhbXC7MR15FssO9b8XFAM_aPQ9_xxoC64wQAvD_BwE

The OP is after the bulkhead between the front seats & load area on a D2 Commercial I think.
The likely option is to look on eBay - but I don't think the D2 Commercial bits come up very often