Thanks for the update Alefor. My shipping details appears very similar to yours, just a week later. I posted it on 14 December then tracked it (via Royal Mail's Parcelforce, then US Postal Service; 3-day delivery is very good service considering I sent it via the post office). It arrived at the RMA facilities in California on the 17th. I asked USPS to send me the signed delivery record via email so I have the name of the person who received the parcel.

So far Entourage's RMA people have not communicated with me though I emailed to ask them if it's at all possible, if they could send me the replacement product before the UK VAT increase on 4 January.

Thank you again for the information. When I received an email from them, I think I would ask them to give me the tracking number though.