Thanks Grant and Gail.

XDL for deadlock is here

https://www.dropbox.com/s/aonjva56erfe9ft/TraceDeadLockXML.xdl?dl=0

Thanks for all the advise... I am going to check the scans / improve the update times - hopefuly this will make a difference - and will definitely check the order of the updates.

I also want to enable the snapshot isolation but wanted to know what it the correct way to enable snapshot isolation ?

I see the MSDN page says:

ALTER DATABASE MyDatabase

SET ALLOW_SNAPSHOT_ISOLATION ON

ALTER DATABASE MyDatabase

SET READ_COMMITTED_SNAPSHOT ON

Do I then need to alter any of the queries ?

I also see notes of some people saying :

ALTER DATABASE >>DATABASE NAME<<

SET READ_COMMITTED_SNAPSHOT ON

GO

SET TRANSACTION ISOLATION LEVEL SNAPSHOT

GO

Thanks for all your help so far.

Steve