I am not sure of what your expectations are for the root killer. Root killer will only stop the plant from re growing i.e kill the plant, it doesn't aid the breakdown of any stumps or roots, leaving them to rot and breakdown will take a long time, only other thing you can do is dig them out I'm afriad, unless anyone else knows of a product on the market that would work.

Your right Dido the stump killers just stop the stump from regrowing... Cromwell if you want to remove the stumps they either need to be ground or dug out.

Grinding can be expensive and you have to have a certain amount of room for the machine. & seven years ago we couldnt get a grinder near so the tree surgeon put a chain on his saw and get them right down to ground level. Just another option?

Thank you, Dido, Moon grower and Drc726. And there is me thinking there will be a'simple' solution hahaha. Probably will try the chain saw suggested by Drc726. Someone did say to try a 'Turfer' ?????? Once again, thank you all. Take care.