They were last seen on Sunday (12 March).
Isobel, 14, is 5’2”, with brown, straight, medium-length hair and dark clothing.
Harley, 16, is 5’2”, with short brown hair and all black, predominantly Puma-branded clothing.
They are believed to have travelled to London and may be using buses and trains.
If you see them, call 999 quoting 1253 of 12/03.