Update: Scored a pair of Phillips +100 Xtremes last night on ebay.
So once i get the beefed up relay in, and replaced the reflectors, I'll try the Phillips. If I'm not convinced there's a difference, I'll switch over to 100/80w or 130/100w plain H4s.
I'm getting a warning buzzer fitted at the same time so that if I leave me headlights on at work (again......) it'll beep at me when I switch off the ignition.