As chance would have it, I had The Pauper's Cookbook, too
(Jocasta Innes IIRC). It disintegrated from use - and yes, you are right, it was "gruel-y", but stuff was edible. I replaced it but it was a New Improved Revised Edition or something, and I didn't like it (plus I was a bit less pov by then) so I gave it to the charity shop.
Unfortunately all "very cheap meal" cook books tend to be a bit Spartan, relying heavily as they do on cabbage, potatoes and porridge, but at least the Pauper's stuff didn't look like cat vomit with a sprig of parsley on it.
My other stalwart was (I think) called Feed your Family for £5/week (Bernadine Lawrence) - again a bit bland, but this time leaning on lentils - and edible.
I can afford corned beef now
!
On a serious, note - no-one has to rely on guest. There are other budget cookbooks out there - cheaper to buy than hers and the food may be (as you say) "Bastille jail tower", but at least no-one looks at it, and looks at the cat litter tray, and wonders which will be worse. . . .
And as you say - they are fun to read. A much better writing style (not that she sets a high bar . . .)