Tiger super six brakes very sponge been bleeding them with a bleed pump still soft every time I bleed a caliper air seems to keep coming out and I've run a full bottle of brake fluid through any ideas

Air trapped in rear callipers. You might have to move calliper around disc so bleed nipple at the top of calliper.
Depending on where callipers are mounted an air pocket gets trapped and the bleed nipple is not at the top

Also it might be worth manually adjusting the rear brakes by winding the piston out to take up clearance ? If the bleed nipples are not at the top of the callipers take off the 2 small mounting bolts and place a piece of wood between the pads to limit the piston travel , gently turn the calliper to get the nipple at the top making sure you don't strain the Flexi hose before bleeding. What type of bleed pump are you using? Vacuum pumps connected to the nipple draw air past the threads and give the impression there is air in the system. My preference is to use a pressure bleeder , the Easibleed works well but follow the instructions .If you have rubber type Flexi hose it's possible to clamp each hose in turn to identify which brake circuit is causing problems. DO NOT CLAMP STAINLESS COVERED HOSES. Is the car a new build? Are the brake pedal/master cylinder pushrods correctly adjusted?

No it's not a new build and the pump is a hand pump that goes on the nipple the brakes have never been very good

Try pressure bleeding, an Easibleed is less than £20

I used ezibleed and still had air in system. I reverted back to the old fashioned method. Need 2 people but it worked better for me.