Thanks John.
James from support also sent me the info below, I’ve forwarded that in to Paul at member press to look at.
“Thanks for the email.
I had a look at the discussion and just to add my input perhaps you could have the guys over at Memberpress also hook into the acf_the_content global filter for getting the acf content within WYSIWYG custom fields.
Please have a look at the following resource page for more info: http://hookr.io/filters/acf_the_content/
I hope this helps.”