I've been a user for a very long time without realising the true potential. I've picked up the odd fix here & there, sometimes in strange places - without understanding the true nature of the product.
For many years I've used closed cell neoprene as a (car) boot liner, as a (foot) shoe liner, and as a door protector in the garage. Closed cell means that it doesn't absorb water like a sponge, so is a barrier to water.
The Morgan has presented a whole new world of uses, and I rapidly ran out of stock. This lead me to research where to buy replacements on-line, and to explore the specifications, and therefore potential uses.
It's taken me a year to get this far, so here goes:
First comes
standard density neoprene. It is available in various thicknesses, in 1mm increments. Standard spec is black but certain other colours may sometimes be available. This SD neoprene is soft and compressible, but tears easily. It's therefore suitable for gaskets, seals, and places where there is no chance of scuffing, pulling or stretching.
My preferred thickness is 3mm, and 4mm.
Next is
firm grade (FG) Neoprene. This is slightly denser and with greater tear resistance. It's therefore more suitable for harder wearing applications like car boot liners and door protector in the garage. It would not be suitable for dogs paws though, as it would damage too easily. This can be used for wing protectors but must be glued to a backing former such as fibreglass. My preferred thickness is 4mm.
Next comes
high density polyethylene foam (HDPF). This has a slight greyness, and has no visible aeration, unlike the previous specs which are visibly aerated. HDPF has high tear resistence, and will do most jobs well.
Beyond this is
rubber which comes in various 'shore hardnesses'. Generally this falls between 40(soft & elastic) and 80('dead' & hard). Note that rubber sheet is heavy, and not really suitable for Morgans.
All the other specs are very light and are therefore ideal.
Now a few pictures:
This is 4mm HDPF which has been on my garage wall since the early 90's. Now I know what it is!!!!

Here is some rubber sheet - this is a heavy roll.

This shows 3mm, and 4mm standard density neoprene. The FG neoprene and HDPF don't look any different in photos, so I'll spare you a repeat photo!!!!!

As you know, I've used this stuff all over the Mog:
Not covered in a post, but I've lined the back of the over-riders with HDPF to keep the wet & dirt at bay.
Under the front wing I used 4mm standard density as a grommet round the steering column.

The cable tidy under the boonet was 3mm standard density......

The wing protectors were Firm Grade neoprene, as were the small protectors......

Under the spare wheel was Firm Grade, and to line my spare wheel security device and tool tray I used 3mm standard density.
This is my chosen supplier:

If you need advice, speak to Steve Nuttall, who has been a great help to me in sorting this out. Service and delivery are excellent. Prices at these thicknesses are around £25 - £30 for two square metres. Thicker sheets will be progressively more expensive.
I think that covers it - any questions, let me know.