I remembered that Citrix provided a cut down version of XenDesktop called "Express Edition" which allowed people to use the core of the product for up to 10 connections.
This was great for lab environments, or people studying for exams.
Whilst trying to apply a XenDesktop Express Edition licence to XenDesktop 7.1 I found it didn't work.
I looked at the SA dates of the licence you download from www.citrix.com/activateXDexpress and it appears to be 2012.0217 which is quite old.
According the console the SA date required for licences needs to be 2013.0522.
This is confusing, because the Licence console within Citrix Studio is telling me to go to www.citrix.com/activateXDexpress
Anyway, I posted a question on Citrix Discussions and it looks like Citrix have removed the Express Edition from XenDesktop 7.1. It is a shame, but nevermind.
To add insult to injury the inbuilt 30 day trial licence ran out in about 20 days. I installed it on 12/12/2013 and it had finished by 1/1/2014
I understand if Citrix want to remove this edition, but at least remove it from the GUI and stop accepting connections to the website at www.citrix.com/activateXDexpress!