Happened to be in a local town today, there are a couple of antique shops on the quay. I saw a few stoves in a box , one Svea 5 , a Primus 5,a Monitor 5? and a Valor 55. The Primus is in a round tin. All are complete except for the Monitor which is missing the outer cap. When I got home and cleaned them up enough to read the numbers, I noticed that the Valor was rattling. I got the rather reluctant filler cap off and shook it about a bit and a four and a half inch wax pencil fell out.
Yes I suppose using one as a dipstick is feasible. This is the Primus in its tin. I was only looking at the Svea and I was persuaded to buy them all.
Pity that. I'm sure you are kicking yourself for making such a horrible decision as to buy all of these bits of brass. It must have really broken your heart.