Housing costs tenant receiving Housing Benefit from LA and in receipt of UC

I have stumbled upon a client who receives UC but doesn’t receive housing element towards rental costs. They do however continue to receive HB from Local authority. UC have been notified of the decision but have failed to contact.

I’m not sure where to turn to

Is it temporary or supported accommodation?

, we provide what is known as block support which entails for example:
General counselling and support
Assisting with security of dwelling
Assisting with maintenance and safety of the dwelling
Advising and supervising on the use of domestic appliances and equipment
Assisting with arranging minor repairs
Providing life skills in maintaining the property
Assisting to engage with individuals professionals and other bodies.
Arranging adaptations.
Advising of assisting with neighbourhood disputes and relationships.

reply from HO so I think it could be classed as supported for purposes of HB

That sounds like it might fall under supported, but also might not - depending on the extent to which your staff helps with those issues. On the lighter end it sounds similar to the support a HO would offer to tenants in general (some HAs and individual HOs being more helpful than others etc) - that would unlikely qualify as supported accommodation.
There’s a fair amount of caselaw on the topic - one of the likely considerations, as I understand it, would be whether the support provided enables the tenant to occupy the property.

I would want to start by confirm with GCC on what basis they are paying HB at the moment - is it in their records as supported?