Decathlon superstore things do a decently sized and priced tarp.

Tarps & Bivvy Bags do a video of how to do stuff

Sleeping Bag | Sleeping Bags – Tents - Flysheets - Hammocks Ray Mears shop site have a few tarps, but also Clingons, which are very handy things you only need a few of, to connect a line either where there is no attachment hole, or if you've ripped one out!

Reusable All Weather Foil Space Blanket - ADULT - SP Services (UK) Ltd this is cool I think, a survival blanket but heavy enough to last a good few years of use. Eyelets in the corners, silvered on one side red/orange on the other and light enough for leaving in a rucksack for hiking purposes! They also do a very wide range of medical stuff, some of which even with the description I still don't know what its for!

Keyword Product Search --- EE33 Tactical Outfitters
This lot do some very good stuff, but you may find it a bit cheaper elsewhere. Both with them and their sister site Heinnie Haynes don't search for "knife", you'd be there for weeks!

I have a hammock with a zipped on mozzie net and waterproof cover, with a flysheet too. If its hanging with you in it it has pockets under you (outside) for shoes etc, but that also act as an insulative air cushion. I've never tried but you can with two supports like a bike and a small telescopic pole, hold up each end of the hammocks fly and use it on the floor as a tent, and zip up the mozzie bit if there are bugs, or most of the waterproof bit too for a bit more draft proofing. The whole thing is lighter than a tent mainly due to its smallness and not having a groundsheet as such, and is about the size of a shoe when compressed. Not a Hennessey cos as far as I'm aware you can only get into that thru a whole underneath which I don't fancy, but a
Clark Jungle Hammock - Hammock Camping products for backpackers which isn't as cheap now with the exchange rate as it is, but a fab piece of kit!

Google bushcraft, shelter and hammock and you'll find loads of stuff!