windscreen/windshield lower rubber anyone recognize this one

Everyone uses that same design or something very close.  Any of the Speedster builders or parts suppliers in the UK/Euro should have it in stock.  Here in the 'States, both Beck and Vintage Motorcars Inc. should have it as well.  I couldn't find it on the Beck website, but I know they have them, too.

https://www.vintagemotorcarsin...hield-bottom-rubber/

My '88 CMC has flat fiberglass under the windshield glass. It uses an angled aluminum strip that gets riveted to surface.

Here's VM profile -

Here's link to Chesil UK piece (no profile shown)

Chesil Windscreen Base Rubber (westfield-sportscars.co.uk)

Your pictured rubber is a more generic windshield rubber, probably TrimLoc or CRL brand.  Not specific to 356 but it works.  The 356 profile is a bit more complicated as shown in the Vintage link, with a groove for the glass, a groove for the lower track, a bulb to seal the track and a wiper to seal the inside edge.  Not sure where Greg (VS) gets his rubber but we have ours extruded for us and also sell it to several Pcar catalogs.

As for the hump in your body, that is not common or authentic.  Best guess is that it is something added by the manufacturer of your kit.  The original (and most replicas) use a lower track fastened to the body.  Some use a simple L channel, sliced and bent, we make an extrusion that is formed to fit the car.

You can view most of these items on our parts page beckparts.com however I have also been instructing my parts guys to deactivate many of the parts that are slow coming in so we can ensure we have them for our builds, so if something isn't there it is likely temporarily backordered/disabled.