Andy Wade wrote:

On 25/12/2017 18:18, John Rumm wrote:

I feel I have missed something?

Access for inspection and testing? You might not want an earth pit[*]
visible FVSO "indoors".

[*] e.g.https://www.screwfix.com/p/plastic-i...-pit/59527#_=p

I was momentarily surprised that your URL gave the stock position at my
local Screwfix; until I remembered the miracle of cookies.

--

Roger Hayter