Good advice. I can get to a drain further down the line. Don't think the blockage will be there. I think I'll still need to get to my blocked drain but at least if I can release most of the crap by rodding backwards then it would prevent a flood situation in the utility room.
In message , blackbat writes
Brownfield water feature including fountain.
I'd suggest the threaded holes you can see are actually in the frame for the cover so if you do manage to get soemthing to screw into them you'll be pulling the whole cover and base up. Screwdrivers and a spade or if you can still read the moulded/pressed/cast makers mark, a set of keys for that type of cover.
As previously said blackbat, give the cover a few gentle clouts and a bit of leverage and it should move easily - and if you can get some manhole cover keys to fit, so much the better.
Also remember, that if the gentle method fails - and you really have to get into the sewer no matter what at that point - then breaking and replacing the cover may be your only option if the thing really is stuck (unlikely by the way on an internal manhole).
BRG
A follow up if you are interested.
The four tiny holes in the corners housed M8 threads. Tried attaching bolts to them and a cross bar as a handle but lid wouldn't budge.
Then, bingo. The penny dropped - the threads weren't designed to house a key, they were for screws to clamp the lid to the frame. I had been trying to lift the frame :-)
I gave they cover a couple of whacks with a mallet to loosen it. Chipped away some of the concrete around the housing which allowed me to get a cold chisel and crowbar in and it lifted.
Lucky too as there was no overflow from the stack.
Then it was rodding as usual - all done now.
Thanks to all those that replied with advice.
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