Here the values for trainers have only just caught up with their rarity, I suppose as more collectors become educated.... The Parker Hiscock magazine was only approved for use in the .22 Pattern 14 rifle (which became the Patt 14 No1 when the Pattern 14 No2 was introduced) and the .22RF MkIII.

When the Pattern 14 No2 rifle was introduced 5 months after the PH magazine, the LoC entry states the magazine was not retained on the conversion... The same entry states the rifle previously named the Pattern 14 was to be the pattern 14 No1.
I still have found no official notification the PH magazine was to be used in the Pattern 14 No2, and there is no instruction for the mods to the rifle to take the magazine.

My Patt14 no1 has distinct marks in the foreend from using the PH mag, as well as a very worn boltway from the extra upward thrust the mechanism of the magazine put on it. Easy to tell if it ever had one fitted and used....

In Aust the mag easily pulls a grand, the rifles are now overtaking that figure.... I think you should be able to expect 2K for that combination anywhere in the world even though the No2 out numbered the No1 by four to one.