Branding - Admin Bar - External URL - Mailto

Dear Sirs,

I am using the Branding Plugin, and setting up the custom admin bar. I am adding an option for my customers to be able to email me from a link, therefore I am choosing to add;
External Link
Title : Resilient Systems - Email us with a question
URL : mailto:enquiries@resilientsystems.co.uk?subject=Union%20of%20Genius%20Wordpress%20Website%20Enquiry

Now this works for the first time, however if I add a new custom link or edit this option, the URL is replaced by a single '\'. I end up having to ensure that I delete the email link, add/modify my other links, and then add the email link as the last entry.

Is there a fix for this please. Thanks for your support

Kind Regards
Andrew Read