It is in an awkward spot under the floor, waste pipe for shower to the underside of the tray. It is the knurled `nut` about 7 cms in diameter. I just dont havent the strength to loosen it, I have one of those rubber strip thingies but I cant get proper access to use it as I need to work one handed so cant wrap the rubber strip around it.
What would be the best tool for the job?