ACROSS

 1 Bars weren’t able to hold her back, but the place you bought this from obviously does! (5,6)

 9 Furnishing something for one’s extremity. (8)

10 Jackson, for example, was a sort of 18. (6)

11 Heels. (7)

12 This sort of trade is on horseback. (7)

14 Didn’t go supported. (6)

15 This might test your resistance. (8)

17 Is such a statement made when one cleans up? (8)

20 Associated. (6)

22 See 13

24 England was in 1664. (7)

26 In the eye, or near it. (6)

27 Think hard for this! (8)

28 Such handiwork should be found in the North, if one considers the compass. (6-5)

DOWN

 2 A Percy, the original in fact. (9)

 3 Terror did once, in greed as well. (7)

 4 Goads horses. (4)

 5 Ran in most peculiarly to what a modest person seldom overlooks. (7)

 6 1, 2 and 3 are in this class. (5)

 7 So is the gate, and narrow is the way. (6)

 8 Busy with what sounds like an award. (6)

13 and 22 Fellow-Red, perhaps. (5,7)

16 To impart knowledge to a sort of 18 and 50 (changing a compass heading). (9)

18 Wander in confusion. (6)

19 Sherbet on top, ground under. (7)

20 The ballet implies rapid movement. (7)

21 They start off Even-Steven. (6)

23 Israel lost one once. (5)

25 A wise one is sometimes a fool. (4)