Are rather rare - but I do believe the period Parker-Hale catalogues might just have a few more illustrations.  Unfortunately I don't have these...   
The rifle pictured - I quote the owner:
"This was a Special order starting from a BSA Mod 6 Receiver and done by AG Parker, best wood and engraving including on the scope mounts, polished and tuned action, only ran from aprox 1933 till 1941."  Apparently the barrel is relieved on top to mount the scope...
Parker-Hale also scoped the Dewar Target rifle, but they used either a Fecker or something similar - long tube, and long block spacing.   
For a rook, something like a straight-tubed scope at max 4x would be ideal, but eye relief could be a problem though when mounting it as shown.  I'll also check in the Francotte documentation, but I'm afraid there won't be much..

My .02c here.........

I have several low walls and Cadet Martinis in suitable rook chamberings. For best looks I'll go with a low wall every time. For best accuracy & lightest weight I'll chose the Cadet.

I have a Francotte Cadet made for the Victorian Government of Australia prior to their Federation, fitted with a light GM octagon bbl (like Froggie's) in 256 Win Mag. It has a little quarter-rib dovetailed for either the early Kimber/Warne Premier rings or the common 22RF tip-off rings, works well with either. It's currently fitted with a little short 6x Burris straight-tube 1" dia scope that has enough eye relief so that the eyepiece is just forward of the breechblock's rear hinge pin by maybe 1/2" or so. This allows unrestricted removal of the fired case under/behind the scope's eyepiece, and relatively unrestricted access for initial chambering by inserting my index finger under the eyepiece to thrust the cartridge fully into the chamber if needed.

Looks kinda funny with the little short scope but is eminently practical and lightweight. I currently have a 5x Winchester 677 scope at Parsons for refurbishment, will try it on the little Martini when I get it back. I believe the 677 clamp-on type mounts will work on the little quarter-rib just fine even though they're the external-adjustment type.

Am shooting (VBG) for a 5-lb ultimate weight limit. How's that for light? BTW that's not obtainable with a wall, too much steel.
Sounds like a great project, good luck, Joe

Here's a suggestion for an original rook rifle cartridge that is both fun, and accurate. The little 230 Morris, which is actually the world's first .22 centerfire. It's base case is the same as the .22 Hornet, but a whole lot shorter. I make mine from Hornet cases, and even with a full load of Unique, it's still extremely mild, and the Low Wall or Martini more than handles it easily.
Here's the little Morris next to a .25-20 WCF for comparison.
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I have been a little slow to respond as I am on a trip down south. 

Lots of nice replies and excellent ideas.

I have lots of experience with both calibers (.32 H&R Magnum AND the 25/20 WCF). I have a Marlin 1894 (new Model) in 25/20 and it is quite a performer. It'll shoot in the 10 ring of the Official NRA 50 yard target all day long with a squirrel load, an intermediate load and a high speed load (nearly 2200 fps. I consider that excellent for a cast bullet lever action. I have shot a number of squirrels with the 25/20 and it is just a better caliber for the purpose than my all time favorite caliber, the .22 rimfire.

However, the Froggie got me intriqued in the possibility of using the .32 Mag in a light rifle. 

I just realized that I have a TC Contender Action and wood for a light rifle. That would work just fine with either caliber and I only have the cost of the barrel. H-m-m-m! That has definite possibilites....

Dale53

Dale53, Since you already have the Marlin in 25-20, you NEED a rifle in 32 H&R. You spoke of the Contender route, DON'T waste your time on a TC brand (Fox Ridge) barrel in 32 H&R. Been there and done that without much success in both 10" and 24". Bore is .308 and chambers were very sloppy. I'd find someone who could make it in the correct bore if you go that route. 

Ed

Ed and Froggy;
Thank you both for your insight. I will give both suggestions serious consideration. I was thinking of a Bulberry barrel but his web site shows .308 for the bore size. I prefer the "proper" bore size. In fact, when I was shooting hunter pistol, I used a .32 H&R Mag from TC with only fair results. I then bought a JD Jones custom barrel with the correct specs. It shot really well up thru 75 yards but failed at 100 ( I believe because I didn't have the right bullet). I really needed a longer, heavier bullet. I ended up with a .30 Carbine with a 165 gr bullet for GREAT results.

Back to this discussion: my experience with TC barrels paralleled Ed's and Froggy's suggestion just might be the way to go. Anyone got a "throw-away" Contender barrel?

Dale53

MI-shooter;
    I would appreciate info on the .297/230 article if you find the time. Actually I need it like another hole in my head but it is just enough different to get my attention. Just ask Asst!

Thanks
Don 

Dale,

Neck down?  Normally the heel should be a rather tight fit in the unsized case - I seat mine (admittedly in an original .310) just friction tight in fired brass.  Could be you need to play with case length, though in order to get the heeled bullet to chamber.  Enjoy - the original .310 is a real pleasure to shoot, and so is a 32-20, so a hybrid of both should also perform nicely...