The lamp arrived. A rather nasty condition lamp in a parcel full of paraffin. It does appear to be a home made affair but the ring on the top has been brazed in place I think so it is secure. It looks like the columns of the ring once had an outer sleeve of metal on them. I think the tank has been over pressurised at some point as it does not stand up quite straight and wobbles a little on the bowed-out base. I am in no hurry to clean this up!
Oh dear, I guess it wasn't the rare Tilley accessory we were hoping for. Those metal sleeves are the handle attachments upside down and cut down if you look at Christers image on the previous page. Never mind swap the tank for a good one and just use it you might find that top rail useful.