Place Custom Fields Not Saving

Hey

We are in the process of building a website on geodirectory. We have set up several place custom fields to capture more information as customers are submitting their listings. Most of theme are multi select checkboxes.

I have set these up and they are showing on the front end correctly, however we are having issue saving the custom fields. We have imported a few dummy locations, if you go into the admin to edit one of these, select some of the custom fields, and then click save. The first time you do this it selects every checkbox, when you go through and deselect everything apart from the ones you want it then refuses to save any of the checkboxes that are selected.

There are approx 25 checkboxs all in multiselects that this is happening with. Other elements such as just standard selects or text boxes are saving fine, it just seems to be anything in a multiselect

Any help with this is much appreciated

Ben