If you need to diversify then will you diversify into an allied business or a totally new line of business?

It would always be better to diversity the activities in the allied business:  You can use the existing client base and business relations to target your audience through them so the marketing and establishment in the field will be much more easy.

The diversification in some common areas which is possible with the help of a Professional management hiring is also be choosen for unrelated areas.  Some entrepreneurs try both.