Incorporation relief under s. 162 TCGA - definition of 'business'

Do readers have experience of the definition of a business for incorporation relief purposes.

We have a partnership owning a large portfolio of residential and commercial property. They work full time collecting rents, and organising repairs. In some instances they are very hands on with repairs themselves. They have an office and it is a full time job.

Is this a business for s.162 purposes?

Does it make a difference if partnership rental income was shown as rental income in individual partners tax returns rather than a partnership trade? ie no NIC's have been paid therefore it does not look like a business to me.