Plan and help run an event

Help organise an event (namely a party for a new office location opening scheduled for 5 Sep 5.30-7.30) and provide assistance at the event itself too. You must be located in or near Hastings - e.g. Brighton, London, Ashford etc. Would like support to identify people to invite, send out invitations, brainstorm how to attract interest to the event, (for example, should we use a particular speaker?), organise the details of the event, and generally ensure it goes smoothly. Location has already been decided but will need help to organise the food and drinks and other details. Possibly help with post party follow up too. Happy to pay hourly rate but please give a rough estimate for the known aspects of the brief.