User Profile - Sequence contains more than one matching elem

I created a new user profile type on Friday with several additional data fields. I started to edit the template and then left it over the weekend. When I returned to it today I'm presented with the popup error "Sequence contains more than one matching element". This is when viewing either the profile itself or the template editor.

From looking at similar reports of this error from other parts of the application, it would seem I have created a custom field with the same name as one of the regular fields. Problem is I don't know how I can correct this because I can't access the user profile any more. 

Anyone got any ideas what I can do to fix this?

thanks

Hello Nick,

 You can delete any custom fields you have added from the Settings section in the backend. Just go to Administration >> Settings >> ContentView >> Controls and there you can see you custom created profile type with a name ProfileType_YourProfileTypeName. From there you will be able to delete all custom fields that you have added.