Lee,
Yes overlap from the previous attempt, someone expecting FSC to be the answer and not going back over it with a lance or the FSC again. Maybe 1 pass only when 2 is needed?
Chris,
Hypo can/will reduce the stripping effect, but 3:1 might not be strong enough as you are trying to remove ingrained dirt etc from the time before, 1:1 after pre-wetting then clean, I'd for go lance cleaning on this anyway
Tom,
Got your email mate, have replied, if you can get back to me asap then see you tomorrow PM.