Disappointing. It's more the principle than anything else. An RF4 Motorglider has a wingspan almost identical to a 172!
Why they couldn't charge in-between the two SEP classes I don't know, £15 would've been fair but this is clearly a cash cow against motorgliders. They may have invested in their facilities but there's no Mogas for us or even a card machine! Ah well, plenty of other places to visit instead....