Many thanks all!
Now the buyer want us to empty the fosse- tricky from Devon UK- and it's one of those fosses with a huge lid (originally concrete- we replaced with a galvanised metal lid, (weighs 53 kg) covered in plastic, sand and then concrete slabs.
Trouble is the fosse has only been looked at 3 times since 2006
1/ when we had roots in the pipes- emptied - but with little in it
2/ new lid fitted - also near empty
3/ inspection 2019 by water authorities (Siveer in the Vienne) also near empty and not been able to go to France during 2020/2021 - just a week Nov 2021 to get the place ready to sell.
Seriously reluctant as accepted 10,000 reduction and lost on 2006 purchase price and spent on new oak kitchen/2 new bathrooms/ dev'ment started for gite - new corner kitchen made plus new carpets, and made new main bedroom on top floor.
Estate agent says we must, but yet another deduction from the sale! is this true? usual? he says the emptying company must open it- but no doubt might well leave a mess.. Help! any ideas advice? and hard to get there at present, we have to to empty the place, but not until we know we have sold.
With gratitude - so stressed by all these demands...