Calling all Brits

Several weeks ago I had a fabulous success after asking for help from my faithful readers on a problem that arose while I was cataloguing the panels in the International Honor Quilt project.  That cry for help was for translating or transliterating some Inuit words embroidered on a panel made in northern Quebec, and amazingly, within a couple of hours I had more than one volunteer!

Now I have another cry for help, but this one on the other side of the ocean.  I need someone more familiar with British culinary customs than I am.

This panel -- executed in beautiful needlepoint -- was made to honor Isabella Beeton, the famous early cookbook writer, and its centerpiece is this elaborate food fantasia.  The person who catalogued the panels 20 years ago thought it was a roast, but I don't, despite the lethally sharp knife in the background.  Is it some kind of Christmas pudding?  And what's the little white cloud of steam being emitted at top right?

I'll be wildly grateful for any help you can provide!