What constitutes a business asset

I am considering advising an appeal in this case but I thought I would outline it here in case it is complete non-starter.

Cl owned a rental property when they claimed UC. Despite this the UC was paid ( it is not known if the cl declared the property in their claim?).  A while later they took out a personal loan to buy a second rental property but did not declare the loan or the acquisition of the second property to UC. UC then found out and raised a very large overpayment.
The cl is self employed and at the time it appears that the rental of the house or houses was only part of their wider business. Their other business interests were in the arts and not connected to property letting or anything concerned with property renovation, letting or maintenance.

It seems that UC accepted a claim from the cl as a self employed person so they knew there was some economic activity going on.

I can see from the HMRC property manual that letting one or more houses is not considered a trade or profession but would letting two houses be considered a business, especially if it was part of a wider but unrelated portfolio. If it could be considered a business then we might argue that the loan and the second property were funds or assets risked in the business and should be ignored as capital for UC al the time the cl continued to work in the business.

I would be glad for any observations, I don’t want to raise any false hopes with the cl if it is out of the question.

See this thread in which Charles schools us about property businesses.  The long and the short of it is that the property won’t be disregarded unless it is a trade (narrow subcategory) despite being a business (wider category)