“Subsection (3) requires the court to have regard to ‘all the circumstances of the case’ but singles out six matters for particular mention. These six present a curious hotchpotch. ‘The delay’ referred to in paragraph (a) must be the same delay as in paragraph (b); so it means the delay after the primary limitation period expired. It is the length of this delay (in the instant case 37 days) and the reasons for it that matter under paragraph (a).”