Look for email from Redflow called "Redflow Limited Non Renounceable Rights Issue" sent around 3pm on 24/04/2019.
There will be a link with the text
"You can access your Personalised Entitlement and Acceptance Form and a copy of the Offer Booklet by clicking here and following the validation process using your SRN/HIN, Surname or Company Name and Postcode."
That's how we did ours.