Setting Up A 'Temperate' Pond

There is another benefit to having gravel on the bottom - it will be home to a whole host of micro-organisms that are of benefit to a tank/pond.

Yep, I am going to go with the gravel. I have also ordered a few aquatic planters, liner and aquatic soil.
I will probably get a few Aponotegen Henkelianus for the planters they grow to about 40cm and will be OK with the temperature. I was also thinking about Hornwort as a stem plant.

The aponogeton helenkus have lovely leaves, they'll look fantastic. 

I hadn't noticed that @Sue
I read it as hornwort 

I've added homework, I mean hornwort , to my tank recently. I like it and the way it drapes - a lovely canopy effect - but is a downside: the fish food gets trapped in it, so I have to give it a prodding post-mealtimes to release the food particles caught up in it.

[Message edited. I had thought there was a second downside but, having re-investigated just to be sure, I realise I was wrong and so have reneged the second downside I had mentioned.]

I recently purchased a couple of bags of river pebbles from a local hardware store. They were classified as suitable for aquatic use. 1 bag has been washed and spread out over half of the base of the pond. I can actually see the fish now without too much difficulty. The other half will be completed in a couple of days.
The Aponotogen Henkelianus (4 bulbs) have been planted in a basket. I have used Westland aquatic soil for this purpose. I have also got 1 sprig of hornwort and placed this in the same planter temporarily until I put another one in place. The planters are 23  x 23 x 13 so I would imagine 1 would be OK for the 4 Aponogeton bulbs. I can always relocate a couple of bulbs at a later date.
I am going to place the rocks covered in Java Moss next to the planters hoping that the moss will creep over the exterior mesh to disguise it.
I am also considering cutting a hole in the side of one of the planters and upturning it to create a ‘cave’. I have some small Java Fern plantlets and a Anubias to attach to the mesh. These should eventually cover it.
The Java Moss is growing profusely so I would imagine it will start spreading across the pebbles as well.
I have also added a dozen Amano Shrimp to assist with Algae removal.
I would also like to add some more fish. I’m thinking either Golden Barbs or Odessa Barbs (perhaps both).
Stocking would be 12 x Golden or 6 x Golden + 6 x Odessa.
I think these would complement the Shiners and WCMMs.

That sounds absolutely brilliant   

I would never have thought about keeping shrimp outdoors, though of course you can with your heated system. Like the idea of how you're doing the planting, including the cave idea... or could it be part of a raised area of the pond I wonder???

Must be great being able to see the fish more now... I cam imagine you wanting to get fish which look different from above... something most of us never have to think about!

Couple of pics of the bottom of the pond with the river pebbles in place. The Java Moss attached to the rocks look almost 'fern like' from above.  You can also see the top of the hornwort which has now reached the surface. It must be growing about 4" a day. The Aponotogen bulbs have also started sprouting leaves.

Great pics Dave... 

I can't fault your logic @daveyng