Classic car heat insulation foil help

I need to put some heat insulation in my Austin-Healey but have no idea what kind to get. I need one kind to stick to the bulkhead and other vertical surfaces but a different kind to put on the underside of the floor mats and gearbox tunnel so I can remove and dry them off if they get rained on. I guess it’s possible to use the same product there since the carpets should remain flat. I simply don’t know which product to buy and there are endless options online.

There’s a huge amount of heat coming from the engine into the gearbox tunnel via the removable bulkhead that joins tunnel and the actual bulkhead of the car and I’m wondering about sticking reflective heat insulation on the inside of both.

Please let me know if you have any experience of heat insulation and can recommend a suitable product or products.