Ray,
The tender on your kitbashed Mike (nice work) looks to me like it could be a Varney. I have a 1953 Varney catalogue that shows a very similar tender....they call it a "Diecast Dilly" and label it a "Varney value at $4.00".
As for the tender on your John English Mike, as pjb pointed out, it's not the original. I have an English Pacific (same boiler and tender as the Mike) bought used in the '50's. Its been through several incarnations and presently has a Kemtron all-weather cab, Elesco fwh, and a scratchbuilt tender. It still runs well. It also has the valve gear: the instructions show it as Central Valley #K12, available separately at $2.95.
(I just installed pick-up shoes to compliment the unplated brass drivers and plan on removing the Elesco and changing back to a regular cab.) I'm planning to use the tender from a Bachmann 2-8-0 to give this loco a "family" appearance with the 2-8-0's that I use in freight service.
I still have the original tender, less the trucks and front steps. Part of the coal load has also been filed off; in an earlier life this had been converted to an oil tender. Also, the rivets, (large) on the rear of the tender have been filed off; can't remember why I did that.
The instructions show the price as $19.95 but there is no date shown. There is a price of $29.95 hand-written on the box, probably quite a sum when my Dad bought it in the mid-'50's.
I also have the 0-4-0 Yardgoat, an appropriate name. The loco never ran well (it was given to me, used, by a friend of my Dad's). I dolled it up a bit cosmetically, but even when it ran, it wouldn't pull much. The loco is on my layout however, sitting in the weeds behind the car shop...scenery, never to run (poorly) again. The slopeback tender, more or less intact, sits in its original box.
Good luck in your search for a useable tender for your Mikado.
Wayne