The correct DNS records for our Brixly Workspace emails are as follows...

MX Record: 

Priority 10 | mx1.spamfiltering.io
Priority 10 | mx2.spamfiltering.io

SpamExperts Downstream:

You should set the destination to the below: (see https://support.brixly.uk/knowledgebase/article/spamexperts-configuring-mail-destinations-downstream for setting the destination)

mail-01.hostns.io

SPF  / TXT Record: 

v=spf1 ip4:23.88.6.16 +a +mx +include:relay.mailchannels.net -all