Alternative Bookies in the UK to place big bets?

[David85]

Are there any specialist betting agents that I can use to place a bet of £20,000?

In the UK, Whenever I attempt this via PaddyPower, WilliamHill, etc, its impossible, they basically assume I know something they dont and decline.
Often telling me they will take £500 but not anymore...

Also I was banned on betfair exchange 6 years ago, and none of there live chat ever works, or when it does they refuse to re-open.

What are my options?

[ODPaul82]

If you're banned from BF you could consider betdaq but it depends on what markets you're trying to get £20k onto
Liquidity definitely not as good as BF but in theory if you place in chunks you should be able to get it all on