Shower tray removal

[Oldyune]

Trying to replace a deep green shower tray with a modern low lipped version.
Discovered that the step against the tray is concrete cast institute with what looks to be zinc ties disappearing into the plasterboard wall ! Also zinc between tray and concrete.
Concrete is 4" high , 4 deep and 760 wide and sits on chipboard floor as far as I can tell. Anyone met this before ? Had hopped would be timber or blocks but all one piece.
My time with a sledgehammer is well past so open to suggestions !

 

[Aquaheat]

SDS with roto stop and a point and chisel. Always work towards an open space as it breaks up easier. Once you have created a few breaks in it it will fly up.

Jon

 

[Oldyune]

That was my thoughts too, unfortunately half an hour of effort including drilling a line of holes from the two open faces didn't quite cut it in half . Both the drill and me thought we were too hot to carry on . It seems to be a better concrete than they have layed in the drive ! May have to hire a demolition drill next ?