Hi Minno,
4d - 4 letter "green is one" (think food) + 3 letter "secure" (as verb) - definition is "seat" (a very laid back type of one)
5d - 4 letter "lover" + single letter "tango" and single letter "kelly ultimately" - definition is "grace"
Hi Neville,
12a - this a very odd looking word I'd never heard of - It's "migraine oddly" (it looks like it gives you nonsense but it is correct) then 2 letter "Guinea exhausted" - definition is "with doctor"