Subtitle inflation

I was watching the encoloured version of Tony Hancock being a Blood Donor with the subtitles still switched on from previous viewing.
    He was going on about his charity donations where ‘a tenner’ appeared on the screen. The rest of the gifts were just pocket change and what he actually said was ‘a tanner’.
    But maybe whoever was doing the titles was too young to know about sixpences.
p.s. “Have you got any mints?” when talking about the hospital food.
    Have they never heard of mince, either?