I've a web service which has been running for some time.

The web service retrieves order batches from a database so has quite a deep
class structure.

The class structure is based on an xsd which generates teh c# classes which
get filled by the database which then get pushed down the wire by the web
server.  Standard stuff.

The problem is that the web service client sometimes decides to change the
type that is returned.

So the Order is of type (go on, guess - yes) 'Order' and it sits in an
OrderBatchType.

The Web service is specced to return an Order object.  However, the client
sees this as an OrderBatchTypeOrder.  

This seems to happen after a change to the server side class structure
(adding some properties) and an update.

Thing is this happened 6 months ago and I struggled for some time with it. I
finally got it working again, but I have now no idea how :(

So what can make the client return a type which is different (in name at
least) to that declared and sent by the server?  - and how do I fix it!?

Iain