Hi everyone, here is the reply from the manufacturer
"Regarding your question: the filter we ship with the bracket is already equipped with a non-draining valve, so there's no need for a very long central bracket duct."
Having had a discussion with another friend/mechanic, he feels that with a non return valve in the filter, it should present no problems. And Tim, thanks for raising this so we were able to seek clarity and re-assurance
However, should anyone want to change their mind following this discussion, please let me know asap
Thanks