Grab rails

I have the Newchurch and the wife wants a grab rail, not to hold onto but to stop her butt sliding. Bought a chrome Bonnie from square deals but I think it needs to be black now. Not actually fitted it but it seems huge. The seat is quite contoured and was looking for something non intrusive looks wise. The new street twin grabby looks more what I need does any one now if it's compatible? If not thinking o may have to go custom! As the streets is £100 it may not be a bad idea!