Can't comment about anywhere else b ut in scotland there were always 2-3 guys who everyone knew chucked it but that never got called, so long as you don't make it anywhere near playing pro you'd be very unlucky not to get away with it.(Thats anyone who cuhucks it, rather than Tim specifically)
To be fair, I've been umpires by county level umpires in that time. Hope they know what they are doing
Same as acktar most truly modern quick bowlers have it