Can you not get a bit further up the road? We found another place to breakfast in the post-Little-Chef apocalypse that is the A1. It's a little pub/hotel by 'side of 'road somewhere near Stibbington (though not the legendary diner itself). We sat there in the window seat eating our breakfast and watching cars go by. So romantic!
We'll be leaving after work on Thursday, so with luck Peterborough can be reached by 8 pm - in time for a nice meal and an early night. Plus, bear in mind that we're generally on the road by 6 am, so we reach Ulverston for lunch by 12, into Booths for supplies, arrive cottage (whose location is described as 'high on a fellside above the Duddon Valley, access only really suitable with a 4x4) for about 3.
This is all planned like a military operation.
I'm interested in your breakfast location. Stibbington, you say?