I'm really struggling today with this.
5A Number to double by adding part of 22
seven letters : possibly ?a???a?
13D Go for it having no alternative
three letters ??t
I've got more on 5A:
it's now ?a?v?a? - 22 down is RIGA but I don't think it's relevant as the 22nd letter of the alphabet is V !! - I could be wrong though !!