Notice the transition from bonnet to A-post to door, in particular the mini-contours on either side of the gaps. Heavy. An indication of a lot of plastic filler.
Interestingly, there was no such thing as a “series 1” either - it was just called an “E-type” as there wasn’t any anticipation of having to rename later models. So a “2.5” is just as made up as a “1” or “Series1.5” or “Series 1.25”, although the last few names are at least in common usage.
The gap between the front of the door and trailing edge of the B-Post in an E-type narrows as the door is opened. The two edges will tolerate very little filler. Excess filler and/or too narrow a gap and you’ll peel paint. The “solution” is to make the front door gap much wider than the gap at the shut panel and/or taper the edges. Either approach looks like crap.
I think what’s truly amazing is that a hand-built car like this could be engineered, assembled and produced for a profit at its price point over its 12 years of production.