Canadian AIP (RAC 4.5.2) stipulates overhead join at uncontrolled airfields and defines it quite clearly.
FYI:
Cross midfield at 500' above circuit height descending on upwind side (your deadside) and recrossing midfield at circuit height to join mid downwind. This can mean some too-ing and fro-ing if your arrival path takes you over the upwind side initially. Circuit height is standard 1000'agl and circuits left handed unless stipulated differently in CFS under PRO section.
With a modest number of NORDO a/c here, I have found it prudent to be obsessional about following this rule for the last 2 years or so.
I would be surprised if the UK CAA doesn't have something definitive in print - it seems to for pretty much everything else
