Hi
Just had this with an La, waiting for 7 months!
Phone calls on a weekly basis, re submitted invoice, loads of promises to pay etc, etc
Finally had enough and told them if they now don't pay it will be 7 months interest and fines + court. They have still delayed but spoke to them yesterday (kept everything friendly) and the cheque is now being dispatched (£350.00)
As always with an LA we are reluctant to pursue this course of action as we always hope for more work, but they haven't given any to me since, so I won't be losing much.
Regards
Martin 
Cheque will be here tomorrow (oh happy days )