There is a wonderful free online map of late eighteenth century London here.
In that, is of course grub street, (5 across and 1 down).
Here it is, out of the context of the rest of the map.
I have just read a book on 'The Grub Street Journal' and will be condensing that and picking out some good bits soon, and am now on 2 books about Grub Street itself, so that will be forthcoming.
When I am not knackered after going back from work anyway.