Thanks. Updated.
I've also got to the bottom of which event the Warning sets came from. At 18:50 on the Mampi Swift set, Five Alive says "tonight you are celebrating the Atmosphere Magazine, the 6th birthday bash".
Warning 'proudly presents Atmosphere Magazine's 6th Birthday Payback' was held on 10th October 1998. All the DJ's except Mickey Finn were on the flyer. He must have covered for someone.
I guess I was way off with the April/May estimate on the date.