Next morning the final assault started.
The pillar was fixed and rock solid. So in it went. Inevitably there was a little more Dremeling to do to get all three pillars, and the roof to fit perfectly against each other, the wood and the tank, but the work was minor next to the hours it's taken create them.

A couple of daylight photos, so lots of reflections off the glass I'm afraid. But it shows the cave in it's final stage … less substrate.
A little water was then added and attention turned to the plants.
Having initially thought the Crypts and Hair Grass looked smaller than expected (though in different ways) I take it all back. I'm pretty impressed with what
www.plantsalive.co.uk have supplied. I think I'd expected each pot to be pretty much a single plant, but there were about 3 Swords to each pot, 6 Crypts, and from 7 pots of Hair Grass I got about 70 little clumps. Certainly the Swords and Hair Grass have exceeded my hopes. The crypts were still smaller than I expected, only a coupe of small leaves each and on small thin stems, but again I have to say that I have no previous experience and nothing to compare this with.
(Not the best background to show off the plants
😳 )

Amazons

Crypts, with the root trimmings by the side.

Hair Grass, again with the root trimmings by the side.
When it came to planting, I took a lead from the YouTube videos from TGM
The placement has changed form the original plan and this has largely been a result of the quantities of plants and the available planting space I've actually ended up with.
For the Swords I took off the worst damaged leaves, though there were few. I couldn't bring myself to pull too much off. And although the video suggests trimming roots, these were the first plants I tackled and couldn't bring myself to do this. As the plants were taller than expected I've planted these at the sides.
Getting a little braver, I did trim the roots for the Crypts. And as there were more than I expected these have taken up most of the middle foreground. As these felt quite fragile these were quite fiddly to plant.
The Hair Grass also divided up into far more little clumps than I expected and although I had originally planned to have some of the Hair Grass taking up the foreground, It has all ended up on the roof of the cave.
Although the “correct way” to plant plants seems to be using tweezers, I didn't seen the need to spend money on something I would rarely use. The Swords and Crypts I just used my fingers to plant. With the Hair Grass I used a chopstick as a dibber which worked surprisingly well.
And on that note, as this posting seems increasingly rambling, I think it's time to let the pictures do the talking.

Front view. (You can just about see the crypts at the front.)

Swords at the left.

And Swords at the right.

And the roof of the cave, now covered with adakama and Hair Grass planted.
Thread
I'm pretty pleased with how it's all turned out but I'm wondering about moving the crypts from infront of the cave – as they grow they will probably obscure the front of the cave, and being able to see into it was largely the point of it. I'll possibly move some Hair Grass down to the front.
All comments, and more importantly recommendations and suggestions, would be very, very welcome.