@Steve Giller Thank you, I did find this myself and didn't action on the basis of the warning and reading the full thread. Another thread was also similarly cautioned against.
I was looking for a stable/supported long term solution, on the assumption that I can't be the only person who needs to do this, but I guess it's not possible.
Victor has advised other users that the Workflow is not a code supporting place, so I wondered if there was anything that would handle these requirements that I might have missed.
Apologies.