Arkwright leads in new Open All Hours (4)
I believe the answer is:
noah
'arkwright' is the definition.
(I've seen this before)
'leads in new open all hours' is the wordplay.
'leads in' indicates taking the first letters (I've seen 'lead in' mean this).
The initial letters of 'new open all hours' is 'NOAH'.
(Other definitions for noah that I've seen before include "Early boatman" , "Ark-builder" , "Oh, an ark man" , "Patriarch who saved his family and all the animals from drowning" , "Biblical patriarch" .)