I would love to implement this for my discussion forum on http://www.spainexpat.com, but we have already upgraded to EE 6 and Discussion Forum v5. Is it compatible?

Generally, “Discussion Forum v5” needs more context to determine compatibility, as it likely refers to a specific software version (e.g., Invision Community 5, IBM Connections v5.5). Without knowing the exact platform, definitive compatibility with “ConsumerUK” (which seems to be a UK consumer advocacy body or a related forum) cannot be confirmed.