Here's a loop if you want z ride to return to the clubhouse. Just over 60 km (so almost 40 miles) in a clockwise direction, showing how nice the countryside around Corby can be.
Here are some routes that we regularly use for club runs. Use the Categories to limit the routes you see. The compass points relate to where the ride goes from the clubhouse. Routes can be downloaded for your cycle computer, either directly as a GPX or via Strava for TCX.