If another W1 Return, for the same warehouse, is being modified by another user then the AAD page will be 'locked'. This is for your benefit to make sure that AAD data is always showing the current view. The page will remain 'locked' until the original user closes the W1 Return. In these circumstances, we advise you to complete the rest of the Declaration and save the data. You will then have to wait until the AAD page becomes unlocked, before you submit your Declaration.
If this means that your Declaration will be late please contact the eCustomer Support Helpdesk on 0300 200 3701 who will notify the National Warehouse Return Centre (NWRC) in Glasgow that you are waiting to submit your W1 Return.