"Any further explanation on that £150 million saving "leveller"??"

Certainly. The Windsors themselves admit to £40 million. What they don't add is the bill for security, estimated by The Times at over £100 million; unpaid taxes, conservatively estimated at in excess of £5.5 million; Grant in Aid to Charles of £2 million; and costs met by local councils for visits etc. conservatively estimated by Republic, based on Freedon of Information requests from local councils, at in excess of £10 million. So, the £150 million is, in effect, on the low side.

Do you have figures that contradict these? I'd be interested in seeing them.