That looks very much like the original Carlyle body with added front end smileyness, to me!Not sure if this one falls into the latter category, being more of a rebody, but as far as I'm aware, this was the only ZigZag bodied Dennis Dart, RIB 7002 - originally Carlyle bodied IIRC.
RML TRAVEL ZIG ZAG BODIED DENNIS DART RIB 7220
A unique bus in the RML Travel fleet was this Dennis Dart with its unique Zig Zag body RIB 7002,seen here at Birches Headwww.flickr.com
(Not my photo)