last two - 17d salesman in major city brought up to be ruler (7) - *M*E*** - is it emperor - if so why?
23a mounted guide after one animal (9) - *O*T*L*** - ???...
last 2 - 18d Heath grabs front of tractor engine (5) - *O*O* - is it motor and if so, why? 20a carriage driver has the ability to catch group of doctors (6) - C*B*A* - all I can think is cabbal but...
Last two-
14d racecourse appliance on the radio (9) - ***C*S*E* - it could be Lancaster, Leicester, Tadcaster or Towcester - which?
15a bird going through doot to landing (7) *R***A* - ???...