Have you tried taskers, they should be able to help 👍

I use a normal pillow Inside a trakker pillow case washed regually so it smells like home 😂.
You will have no problem folding your bedchair with it inside plus your bag and Bivvy table 👍

Always take a small hand brush myself when using a groundsheet, not very effective with wet sticky mud like but what do you do ? Plus the brush doesn't weigh much 😂

I own the 1 man version of this Bivvy, don't use it anymore as I snapped one of the pole spigots, tried to email fox but I'm still waiting for a reply 18 months later 😂.
I always had trouble taking poles apart, make sure they are clear of any grit and give them a lube. 👍

I got back into carp fishing a couple of years ago after a good break.
I started with a budget of £700 and managed to get all the basics (I went with fox EOS rods and EOS10000), still got them now, try to take advantage of any shop discounts, no expensive rods, bivvy, bed, they are all materialistic and don't help to put fish on the bank.
I'd rather spend more on quality bait, good quality terminal tackle and fish care.
In Time you'll see what you need to upgrade/add to your set up, and go from there 👍

Taskers angling are doing 12 x NGT 450g canisters for £39.99

https://www.taskers-angling.co.uk/products/ngtbutanegas450g12pack?_pos=5&_sid=346a6a463&_ss=r