It is being held on Saturday, June 25 from 2pm to 5pm.
“This is our first ever garden party and we are really excited about it,” said Ninette Edwards, team member and organiser.
“We’re planning a whole host of exciting displays and activities including technical rope rescue displays, search activities that everyone can take part in, and a chance to meet our search dogs and see them work.
"There will be tours of our emergency vehicles, an opportunity to learn CPR, and of course, afternoon tea with Prosecco and Pimms on the lawn.”
Ninette added: “It’s a chance for us to show the public just what we do and for people to gain an insight into how we carry out our work.
"Our team is entirely funded through public donations and our running costs last year were £65,000.
“We’ll be holding a raffle and an auction with some fantastic prizes.”
The 13th century castle, set in stunning grounds, is the home of Sir Humphry Wakefield who is the Honorary President of the team.
“We’re absolutely thrilled to have Sir Humphry hosting the event and it will give those attending a wonderful opportunity to explore the castle grounds,” said Ninette.
“We’re asking that anyone interested in coming along, to visit the team website at www.nnpmrt.org and click on the supporters link. You can become a supporter there, and get an invitation.”