Spotwalla location page is at
https://spotwalla.com/locationViewer.php?id=360
When it's active, this Saturday, it'll show the last known position of any users who've signed up for it which you can do by clicking
here, filling out the form then running a SPOT or similar on the day.
The form will ask you for the join password which is
ibauk; which of your devices you'll be using on the day; a 'location id' (Your name or initials or rally # or whatever) and which types of message (OK, help, tracking, custom) you wish to have included.
Hopefully many entrants will do this and it'll make for a lively overview of the rally. I'll post a link to it on the front page of ironbutt.co.uk during the rally.