There were many more escapes than 25; but I would accept that the number would be correct for the number of prisoners not only escaping from the camp; but also making it back to Britain (of course there were also many who evaded capture and got home but were never in camps). As an example in the real Great Escape, there were 70+ escapers who made it through the tunnel (out of 100 planned - the tunnel was discovered during the escape). Of these 2 made it to neutral territory and 50 were executed (illegally according to the Geneve Convention) upon recapture by thr Germans. Of course the same camp had also been the site of the earlier 'Wooden Horse' Escape; with 2 making a successful 'Home Run'. Colditz is also famous for attempted escapes (one or two being home runs), and Colditz was only used for 'awkward' prisoners, most of whom had made at least one escape attempt.
Many war-related (and especially RAF) Museums, including Hendon and Tangmere, have escape supplies exhibitions; not only the Monopoly sets but also packs of playing cards containing maps and even equipment (including money) moulded inside gramophone records.
As well as items supplied via the Red Cross (who were unaware of their role), RAF uniforms also had escape and evasion features, including such things as magnetic trouser buttons (usually not those described in a recent QI, which unscrewed to reveal a small standard compass, but instead magnetized so that the button indicated north when resting on a point moulded onto another button), but also maps (some inside jacket linings so that hopefully they would not be found during a search) and the fact that the standard RAF flying boot could be converted to a civilian-style shoe by cutting off the top.
The Swiss and Spanish borders were notoriously 'leaky', generally with mountainous areas complete with civilians willing to act as guides for idealogical of financial reasons; and internment for the prisoners was usually of fairly short duration (some escapers via Spain actually getting to Gibraltar without being intercepted). The French Resistance were also of great help to RAF/USAAF aircrew who had evaded capture; but were usually more reluctant to aid escapers as their identity was often difficult to confirm.