I had my NCS appointment on 6/1 in Richmond and I can highly recommend their service. The OISC professional I dealt with was very thorough and she caught and helped me to correct two mistakes which could have caused processing delays without her intervention.
She posted my application Special Delivery and gave me the tracking number; I looked on the Post Office's website this morning to see that it had been received yesterday by the guaranteed 13:00 delivery.
I'll post again once I receive the Home Office letter of acknowledgement.
Also, for anyone else who has yet to apply, please note that you can request to have your citizenship ceremony held elsewhere than the borough you live in or your closest register office. I requested mine to be held in a different (but nearby) borough because that particular borough offers Saturday ceremonies, and I wanted to be sure my husband and I could attend without work being a consideration, particularly as DH has very little control over his work schedule due to his client commitments.
I had to search around several local borough's websites before I found one that offered Saturday ceremonies, but I think the effort was worthwhile.