Can anyone help with these, please?
13Across: Rock of Gibraltar primarily covered by good course on Spain (6). I have _ R _ N _ E and think it could be GRANGE, but how?
In 15 Across:, how does the letter O stand for "appeal"?
In 5Down: how is "single digit" = TON?
And lastly in 22Down: Email Correspondent, important to get one in place 3,3. PEN PAL. I understand the PAL but how do you get the PEN from "important"? Many thanks.
15a Passing appeal to head of state (5) 5d Single digit about right for rent (4) 15a O-king 5d Tore - 'toe' (digit, about) 'r(ight)' 22d Key pal - 'key' (important) + 'a' (one, in) 'pl(ace)' http://dictionary.reference.com/browse/keypal