Hello Graham - welcome to the community and thank you for sharing this post with us.
I had not heard of this prior to reading your note.
I tried to use this and found the same problem - the “Start Therapy” screen hangs. I notice there is a little error message right at the bottom of the screen and you can easily miss it, but it says “InvalidOperationException …” - this looks like a technical error that might be used by the developers to troubleshoot their app as it does not mean much to an end user like myself.

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I then tried to see if there is a helpdesk you can contact but I found nothing. The UCL website has many contacts but I don’t know if any of them might help.
Having looked at the website, I got the feeling it was almost like a student project that was abandoned after initial release. I couldn’t find any support information and it seems the application was developed and designed over 10 years ago and was compatible with Google Chrome browser and maybe Firefox but not MicroSoft Internet Browser.
Based on this, I feel it is not something that might be usable today as you might need a computer (laptop or desktop) that runs old browsers. With most things being done on mobile phones, internet (web based apps) are not fully functional and tend not to get updated.
I am sorry if I am talking “techie” speak but this seems to me to be a “techie” problem.
I found a link (not sure of this is where you came across this) on the Stroke Association website. Since it (Eye-Search) is being promoted by the Stroke Association, I have contacted them explaining this issue. Once I hear back, I will update on here.
For now, I conclude this is no longer in active use, but I may be wrong.
I note both @khyber and @Susan_Jane have used Eye Search but they may have used it before Mobile phones took off and everything worked on laptops and desktops?
I also tried to run the alternative “Read-Right” suggested by Sue and that didn’t work for me either (I am using a laptop for everything including this forum - god forbid they make it mobile app only
)
UCL is an academic institution and think they have been known to have weak security on their systems making them targets for hackers - I got the message “Your connection isn’t private” when I tried to use Read-Right.
Unfortunately, I guess none of this helps you 
Wishing you all the best.
Namaste|
