Martin
I suspect I may be of some use to you. I was heavily involved in the Framework excavations at both Heathrow and Stansted, and worked on the post-excavation and publication of both. The recording system is quite a big topic, so it might be quite a long discussion
It is worth pointing out too, that the recording system used was part of a much wider approach to the archaeology, which started with a more reflexive (yes, I hate that word, but that's the one we used) approach to the archaeology, involving a staged approach to excavation designed to allow us to target our excavation most effectively. In practice that meant a 2 staged approach to the excavation where a series of targeted interventions were dug and recorded, the sheets checked and entered into the database, finds spot dated and added to the database, and in some cases environmental samples assessed, whilst feature plans were digitised and the sections scanned. All of that was queried on site using a GIS, and the results of the first phase of excavation work used to target further excavation work designed to raise specific queries raised by the initial excavations
Obviously the paper recording system was a major part of this. there was indeed much emphasis placed on interpretation. As others say, interpretation is nothing new, but the principal aim of this was to encourage diggers to think about depositional processes, how the features they excavated are likely to have changed over time, how they related to the wider landscape, and how they are likely to have affected human activity and understanding of the landscape. a big part of this was the grouping of feature fills as well as cuts.
In order to help this process, there were indeed weekly tours of the site, diggers were encouraged to use the GIS to aid with their interpretation, a geo-archaeologist was invited to give seminars on formation processes and the interpretation of specific depositional processes on the site, and there was also a day of lectures on sites in the area and other relevant sites. John Barrett was heavily involved in formulating the academic ethos of the system, and made several trips to the site and lectured to the diggers.
I'm sure if i sat down and thought about it longer, i could probably give you chapter and verse, but these days my brain is weak and full of 10 years of more recent sites. feel free to ask any specific questions you have, and i will do my best to help
i probably do have copies of sheets somewhere, or can at least get hold of them. Bear in mind though, they did evolve over time as we encountered and overcame various issues
As far as I know the system has been used little since. Bear in mind it was designed largely for dealing with excavations of massive areas of landscape, and requires on site finds and IT presence plus an extended program of excavation in order to work at its best - so, time and money... Haven't done many projects like that recently. It was, however, I believe used in a modified form on the excavations on the East Kent Access Rd, although not having worked on that particular project I'm not well placed to say in what form
Hope that helps a little
Rather than me hold forth about the merits or otherwise of the recording system, perhaps it might be easier if you let me know what you want, and I'll try and help where i can