I am hopelessly stuck in the top left-hand corner. Hints on 10ac and 12ac would be welcome, as also the first word of 2 down, which i suspect is 'train' though I am not sure why.
10a "A Roman character embracing Greek one in street (6)"
12a " Take notice of shop's stocktaking" (4) And I think this is PSST--but does note seem too good definitionally.
Psst is in clue and fits definition of "take notice of!"?
I'm not sure if you want an answer but one greek character (13th letter) put in the sound of a Roman number gives a common name for a street?