Turns out my host - BisectHosting - they use multicraft and it has a commands / scheduled commands web interface.
I created a custom command for the cleaning up of items, scheduled it to run at a specific time and recur every 2 hours.
Only problem is that you have to do this for the message and for the cleanup itself.
Eg@ Message recurs every 2 hours, and the cleanup is carried out every 2 hours, but happens 2 minutes after the message etc.