It is definitely pre 1920's, 1907 if I remember correctly. Walls are either English bond or English cross bond (will have to check the neighbours' brick pattern tomorrow to confirm) with one, or several layers, of render accumulated over time... I think I will follow your advice and get a good builder to have a go at the plinths and repair render. I will also will to have a good read about DPC... I must confess I have no f... idea of DPCs
Pre- 20s you may have a pitch layer, a slate layer, or, if you're unlucky, none at all.
Solid walls and lime mortar bring their own problems, as they are more permeable than cement walls, and they need to be and to dry out - cement render and gypsum plaster prevent this happening effectively.
In the long run (if we ever get enough money to do all the house to the right spec) would you recommend going back to original brick and insulating on the inside?
It is definitely pre 1920's, 1907 if I remember correctly. Walls are either English bond or English cross bond (will have to check the neighbours' brick pattern tomorrow to confirm) with one, or several layers, of render accumulated over time... I think I will follow your advice and get a good builder to have a go at the plinths and repair render. I will also will to have a good read about DPC... I must confess I have no f... idea of DPCs