Another dating question, sorry!

26.98mm: is that the seat post? So 27.0mm near as damn-it: that suggests a decent tubing; together with the indications of it being a low-end model, I would plump for it having a 531 main triangle.

The pip on the steerer tube is for one end of a pump, the other end going into an aftermarket band-on pip usually supplied with the pump. Only one pip was fitted as standard to allow for pumps of different sizes.

The pip on the seat stay is to hang the chain on when you take the rear wheel out.

"Fly half way around the world; polish an old bike; go home.": if you'll pay for my ticket, then I'm in!

Seriously, you've got a perfectly decent bike there and while it may have no real financial value, you can get it on the road and looking respectable for next to nothing; and when you do each mile will be priceless.

Duh! Just realised. You wanted the frame seat post measuring.
Yes, I measured the seat stem, I will bring callipers home and re measure. Yep little $$$ value to the old girl, but she still raises a smile. Will post back with correct measurement. Thanks for the offer of a bike polish but the tickets paid for and a second one would make it even longer for the restore to start!
Money doesn't grow on Raleigh's, it goes on them!

No that measurement's fine, one man's post is another's stem: whether you measure the external diameter of the seat post/stem or the internal diameter of the seat tube, it amounts to the same thing and my comments stand.

Your last sentence made me smile, as I look around my flat at four bikes, three frames, half a dozen wheelsets and numerous bars, stems and saddles etc; and that's after I've tidied-up...