I have no idea what a good substitute would be. The 100 may mean 100%. Amazon sells it by the gallon for $38.00 US.
Not in the UK they don't - it's all ultra-expensive "health" stuff, or hair conditioner, or similar, and comes in little tiny pots or bottles... Anyway, I had a slightly closer look at the lube chart, and did a bit of deductive reasoning (probably entirely wrong, knowing me

), which leads me to believe it may be a lube supplied by Houghton Edgar Vaughan

:

I've sent them an e-mail... hopefully they'll reply. Thanks for taking the time to try to puzzle this one out for me

Meantime, I couldn't resist a little play. The first job was to make a chuck key, there being none supplied with the lathe. I couldn't find my square bar stock, so I decided to use one of the arms on the chuck key I made for my dividing head. The bar only needed about 0.020" shaving off to make it fit the 3-jaw chuck - and accuracy wasn't mad important, so I lobbed it at the vice & took very light (0.005") cuts with an end mill:

I invite you to count the number of errors/bad practices I'm indulging in here. I can think of at least three.
Anyway, managing to avoid launching lumps of metal across the shop, I milled down 3 sides by 0.015" each (who can't count? me?). The 4th side wasn't possible with the key in the bottom of the vice due to the right-angled bit. And it's slightly narrower than my parallels. A trial fit showed it was OK anyway, so I left the 4th side un-milled. This is the result:

Nasty, but it allowed me to chuck some bar into the lathe to have a little play.
Oh boy, now the learning begins....
I won't show the results of the first bar, because frankly it's dreadful. I managed to chip the carbide bit that was in place, and mounting a new tool will be a major pain in the posterior - a QCTP is definitely right near the top of the agenda. At first, it seemed that the lathe was in a massive hurry. Observe the chart below:

I wanted the slowest possible feed rate for either sliding or surfacing. 14 is the smallest number, so I set the gearbox accordingly.
Banzai!!! 
The carriage shoots off across the room, and it looks like I'm cutting a really naff thread. WTF??? Shurely this isn't right? I try facing the end of the bar & get a lovely spiral pattern. What's the deal here, do I need some uber-wide bit here? Have I made a massive mistake buying this lathe? I do recall that the minimum number of threads per inch was a comparatively low number. 28, in fact.
Hmm. 28tpi is all the way over the other side of the gearbox.

I remember reading about this on Tony's lathes.co.uk site. Edgwick didn't quote their surfacing/sliding speeds in thousandths per revolution; they described it in cuts per inch! So I'd managed to pick the MAXIMUM speed of the lathe, instead of the minimum!

Adjusted over to 200 "cuts/inch", and got a MUCH better surface finish. Still rough as a bear's arse, but that's because I've chipped my carbide bit.

Oh, and when I clamped the bit in the chuck, I broke the (really really crappy) weld on my chuck key. So I can't get the bar out now.
Hey ho. Tomorrow I shall make a whole new chuck key. One that doesn't have welding on it.
That's all for now!