Presumably the barrow is a Scheduled Ancient Monument and any damage to it would be an offence under the relevant legislation BUT it depends where 'the line' has been drawn to mark the edge of the scheduling.

One guess would be that the line is where the slope of the barrow 'meets' the land surface in which case it would seem (from the pictures) that the cross doesn't encroach in to *this* scheduled area. Only the County Archaeologist (on behalf of English Heritage) can answer that.

Another question is - did the cross have planning permission? If it needed PP then due to the proximity to a (presumably) SAM then the archaeologist would have been a statutory consultee and as the cross is up perhaps the archaeologist had no objections.

It's worth asking the questions but this erection *may* have been legit. A legal minefield!

Cheers

G