Cracks in conservatory.

twopenny

I don't think you should take the internal floor up yet.
From the exterior photos there is a lot of damp where the decking is hard against the brickwork. It has gone down through the decking and stayed damp.
You have lost the mortar in the brickwork and the bricks are damp at the base and one side of the decking against the wall has dropped.

Before anything else remove the near decking bits, cover in wet weather but remove in dry and try to get it dried right out.
Then clean up, remortar externally and when you take the decking right out you can see the situation and deal with it.

I had something similar in the house I moved to where a patio sill had dripped and kept the bricks wet held in by gravel. It was a grubby and knuckle scraping job I did not enjoy but once cleaned up and dried out not difficult to repair.

YoungBlueEyes

Ok floor can stop then. 

Himself is on with it now. 

Thanks ever so much everyone