How to pre-arrange return delivery of documents from UKBA

Hi everyone

In the guidance notes for some particular UKBA application form you can read: "It is our policy to return valuable documents by secure post. If you wish your documents to be returned by other postal service or courier you will need to supply a pre-paid delivery envelope ensuring that the full postage stamps or fees are included."

My personal experience with the UKBA is that they use sometimes Royal Mail standard delivery, sometimes the Special Delivery, for the return of your documents, and that they can also return only some of your documents, whereas your view and the UKBA's view of which of those documents are valuable can be quite different (by which I mean that they can retain also some of those documents that you will need in the future). Also, the more complicated your instructions for the return delivery of your documents are, the more likely the UKBA staff is to ignore them.

Does anyone have any good experience with enclosing some particular kind of stamped envelope or envelope with some pre-payment voucher for the safe return of supporting documents? My volumes of documentary evidence for UKBA tend to be quite bulky, and the biggest pre-paid Royal Mail Special Delivery envelope is still quite small (only for 0.5 kg). Do you know about any handier (and preferably also safer) means of return of the documentary evidence that would be suitable also for a couple of kilos of documents and that would also the UKBA staff be likely to willingly use to return you your documents after processing your application?

Thank you in advance for sharing any valuable experience.