The usual endgame struggle after a relatively quick solve. Does the shading or its "shape" have any relevance? I'm quite sure I've done it properly.
Thanks once again to drxx for his well- judged interventions. You got me over the line yet again.
Finally got there. This would be quite impossible without the internet unless you were a specialist in this particular subject. I did not even recognise the elements in the non-obvious part of the shading, despite lots of grid staring in the right place!
Thanks, xwordfan. I can see what you have done. How to we know this is correct rather than highlighting words like LAMB that are there too and are backwards? I thought the ending would be convincing.