Re:
Well, some progress made today.
Drive side Sugino BB cup removed pretty easily, gave the seat post another dose of GT85 and a Gggggrrrrrrr with the stud pliers, nothing. Gave the stem the GT85 treatment then turned the frame upside down and squirted plenty on the stem wedge. Once it had all disappeared up towards the headset I turned the frame over and discovered the Milreo Course stem has an Imperial allen bolt, so I did some work on my tourer while I tried to remember where the Imperial allen keys are. Gave the seatpost some heat and then another squirt of GT85 and a Ggggrrrrrr... nope. Two hours later with minimum fuss the stem came out, so I figured best of three and Gggggrrrrrr ahhhhgggg, nope. Need to get some coke or plusgas or slide hammer or all three. Seatpost is a 27.0 Birmalux, not that that makes any odds to anyhow.
Dropout to dropout (mid point of the rear) is about 38 1/2", and without the stem and cup the frame is very light and all the tubes 'ring' well.
Frame number is 550 and the BB shell is a casting which has been filed on the underside I assume to remove some casting marks. Also, under the black paint is either a primer or a light powder blue colour, although the Dave Lloyd transfers are original and are water slide, exactly the same as my red frame before restoration.
So some progress and a seat post that I am going to have to get creative with.