Parties at the Gym At the Leatherhead and Dorking Gym Club we have everything to make your party a real success Our facilities include a large pit full of foam rubber, a bouncy castle, ramps, crash mats plus a wide range of equipment and activities. Call us now 01372 377718 Pricelist & FAQ's (PDF) All parties are supervised. Children play in the Gymnasium then have their Birthday Tea on the balcony. Suitable for children up to nine years. Children will get the exclusive use of the gym for 1 hour then birthday tea in the party room for 30 mins. (you will need to bring your own food and drink). The last 15 minutes will be for you to tidy up. Weekdays £200 Weekends £240 for a maximum of 30 Children.