Add User Name/Display Name to Email Template

Morning

I am using a plugin (Booking Manager Pro), which is working fine. The plugin is for booking activity sessions, with an activity advisor needs to approve.

All fine and the permissions are in there for the users. When a booking is made it sends various email out to the activity instructors and the client and so on.

When the booking is approved again it notifies the client via email, now what I would like to do is added the Display Name for the person that was logged in and approved the booking:

i.e. Your Activity instructor is {displayname}

{displayname} being the logged in user that has approved the booking.

Could someone please help me out with the, as I am now at a bit of a loose end as I don’t what to add in the email template to make it work.