On course bookmakers in Victoria must accept bets to a certain limit.
Rails bookies must accept bets to take out $5000 at the price showing. Off the rails bookies must accept bets to take out $2000 I think. Country limits are a bit different.
On course bookies cannot refuse anybody's bet up to these limits if they have the prices on their boards.It is a condition of their licence. If they refused you you could go to the bookmakers supervisors and complain.
Online bookies are a different matter however there is no reason for them to limit certain clients. If they are overexposed they simply lay off elsewhere. Mark Read's agents are highly visible on course at all Melbourne meetings.

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bren250