There is no required separation in the circumstances you describe; provided that the crews have visual contact and the ATCOs are happy, there's no problem. Visual separation is a good way of shifting traffic near aerodromes. No distances are specified. The rules about wake turbulence still apply, but not for a helicopter under a Heavy jet.
Sorry, it really isn't anything to get 'het up' about.
[ 23 July 2001: Message edited by: NorthernSky ]