Hello Peter,
I cannot offer any info regarding a manual windlass but I can show you pictures of the electric Lewmar which I fitted 4 years ago. my objective was to have at least 50m of 7mm chain (had bad experience with rope/chain combo) and also to be able to keep the CQR stowed in the original anchor locker.
I made and fitted a second chamber under the existing one with a new drain hole and mounted a vertical motor windlass on an 'island' fixed inside the original locker, shaped such that a 9Kg CQR would fit around it. I hope the pics show things better than my words.
Best of luck!
rgds
Chris

An absolutely brilliant reply thank you.There is so much in here that I'll have to review it all slowly.One thing I've learnt straight away though is that such a lewmar winch can discharge vertically below.

Great set of pics - I’ve been wondering about fitting an anchor winch. Is there a reason why you wanted to be able to get the anchor in the locker? I once sailed on a boat in Greece which kept the anchor in the roller all the time - wondered whether I could avoid having to create a secondary locker....
Thanks
Bernard