We applied on the 28th of March and the visa centre in Moscow gave great advice on how to package the doc to make it easy for ECO, there did not seem to be any issues
Just make sure where you address it to Sheffield you put the GW number, if its priority and what visa application centre you used on the top right.
Inside we enclosed 3 bundles of doc.
1) original docs
2) copies of original docs
3)Relationship proof (skype, whatsapp, call logs, pictures)
In 1 & 2 we broke it down into categories within plastic covers, with a cover page detailing what was enclosed with the GW number & priority on top right again of each cover page.
Broke it down like this in plastic covers
Application & appendix 2... with English test & tb included, translated Marriage cert
Employment & Financial docs
Accommodation docs.
Other Docs.... util bills, cover letters
The relationship proof was just one folder as really apart from the marriage cert they were all copies and did not need returned.
All the original docs were returned and the copies were kept in Sheffield. It was a fairly painless process for us, no calls to employer or interviews needed