Mark:
Small frame Martinis are one of my favorite guns and the Vickers is an interesting variation, one I'd like to have (although I just spent the toy fund on an Arrieta 578 in 16 gauge, which pretty much emptied the pot). They are far less common than the BSA/Greener/Francotte small frame martini actions. Given the condition of this one, it likely was a privately owned rifle rather than a club gun.
These rifles tend to be as accurate as any of the other Martini actions of the same period, which is to say that they will match all but the highest quality .22 target rifles. Unless the sights have been abused or are badly worn, they are quite precise and allow most accurate, repeatable adjustments. Does your friend have the inserts for the front sight?
The overtravel screw in the trigger guard is aftermarket, as, almost certainly, is the recoil pad, although from the photo it appears that the addition was made not long after the rifle was purchased.
An odd feature of the Vickers Martini is that the barrel and the action are all one piece. No rebarreling there when the bore is shot out or damaged by careless use of the cleaning rod. Except for the stock, that rifle looks to be in nice condition, without a lot of the extra holes these single shot target .22s seem to acquire during their lives. Unfortunately, to my knowledge, no one is making replacement stocks for the Vickers Martini.
Without the damage or with good quality stock repairs, you'd likely get $550-650 on one of the on line gun sale web sites; or a bit more if you can find two buyers who both want one for their Martini collection. With the damage left as is, I'd say $350-450, depending on how badly someone wants it.
Hope this helps.
Rem
