SS/FG in London

Here we have an example of the weakness of expressing gears just by sprocket sizes rather than the actual gear they achieve ('development').

Because I'm old school English, I find the ancient system of expressing the gear in inches by far the easiest to understand - even though this number is, in a sense, arbitary.

I have a memory, from childhood, of sitting in a cafe and working out gears using pen, paper and long division. Now, with a calculator, it's easy - just divide the rear sprocket teeth into the front and multiply by the wheel size. So assuming a modest size 700 tyre to be about 26.5 inches:
44x16 gives 72.9 inches, but 47x18 gives 69.2.

Similar, but I know which I'd rather have to climb Highgate hill.

I'd say both are a bit on the high side for most - If we're talking single freewheel, I'd say it's probably desirable to be slightly lower than you would want for fixed: for every up there is a down!