Cupboard Unit Loose

[ja197]

Has anyone had a problem with the kitchen unit working loose? The front end seems to have a bit of play and rattled particularly well until I wedged a knife between the cabinet and the window trim.... having looked at the book and the unit am I right in thinking that the sink needs to come out just to get at the fastener to tighten this up?? Please tell me not!! Any advice gratefully received.
James