I don't know? I'm not welcome on LxBet which is the fixed arm of tab but I can put as much as I like on the tote.
Of course my bets are in the hundreds not thousands so that maybe the reason I have no problem?

Can't see any reason why they would not except any amount on the tote?
Makes no sense, it's after all a totalizator agency the more you bet the more they earn with 0 risk to them. Different with the fixed odds a smart punter can really hurt them.