Congrats disco!
Yeah we shouldn't be using PAPIs. Like mazzy said they are set for a 3deg glideslode and for airliners. It much better to just do the landing visually, I don't think I've ever done more then glace at them anyway.
I'm down in hampshire for a couple of days, visiting some ground schools. I'll be back in edinburgh on 21st and hopefully will get my PPL asap!