Okay looks now like this:
(
"lead_charge",mtf_battle_mode,charge,
"You lead your men to battle.",
[
(1,mtef_defenders|mtef_team_0,0,aif_start_alarmed,12,[]),
(0,mtef_defenders|mtef_team_0,0,aif_start_alarmed,0,[]),
(4,mtef_attackers|mtef_team_1,0,aif_start_alarmed,12,[]),
(4,mtef_attackers|mtef_team_1,0,aif_start_alarmed,0,[]),
],
[
(ti_on_agent_spawn, 0, 0, [],
[
(store_trigger_param_1, ":agent_no"),
(call_script, "script_agent_reassign_team", ":agent_no"),
]),
(ti_before_mission_start, 0, 0, [], [(assign,"$bash_readiness",0)]),
(0.1, 0, 0, [], [(val_add,"$bash_readiness",1),]),
(0, 0, 0, [(game_key_is_down, gk_defend),(game_key_clicked, gk_attack),],
[(assign,":continue",0),
(get_player_agent_no,":player"),
(agent_is_alive,":player"),
(try_for_range,":shield","itm_wooden_shield","itm_heraldic_mail_with_surcoat"),
(agent_has_item_equipped,":player",":shield"),
(assign,":continue",1),
(end_try),
(eq,":continue",1),
(agent_get_horse,":horse",":player"),
(neg|gt,":horse",0),
(ge,"$bash_readiness",10),
(assign,"$bash_readiness",0),
(call_script,"script_cf_agent_shield_bash",":player"),
]),
(1.0, 0, 0, [],
[(get_player_agent_no,":player"),
(try_for_agents,":agent"),
(agent_is_alive,":agent"),
(agent_is_human,":agent"),
(neq,":agent",":player"),
(agent_get_class ,":class", ":agent"),
(neq,":class",grc_cavalry),
(assign,":continue",0),
(try_for_range,":shield","itm_wooden_shield","itm_heraldic_mail_with_surcoat"),
(agent_has_item_equipped,":agent",":shield"),
(assign,":continue",1),
(end_try),
(eq,":continue",1),
(assign,":chances",0),
(agent_get_team,":team",":agent"),
(agent_get_position,pos1,":agent"),
(try_for_agents,"
ther"),
(agent_is_alive,"
ther"),
(agent_is_human,"
ther"),
(agent_get_class ,":class", "
ther"),
(neq,":class",grc_cavalry),
(agent_get_team,"
therteam","
ther"),
(neq,":team","
therteam"),
(agent_get_position,pos2,"
ther"),
(get_distance_between_positions,":dist",pos1,pos2),
(neg|position_is_behind_position,pos2,pos1),
(lt,":dist",200),
(val_add,":chances",1),
(end_try),
(store_agent_hit_points,":health",":agent",0),
(val_mul,":health",-1),
(val_add,":health",100),
(val_div,":health",10),
(val_mul,":chances",":health"),
(store_random_in_range,":rand",1,25),
(lt,":rand",":chances"),
(call_script,"script_cf_agent_shield_bash",":agent"),
(end_try),]),
common_battle_tab_press,
But doesn't do anything....