Hi Lee,
LENNON is not something you really query. Typically you upload your daily sales via SFTP. The format (SDCI+) is quite arcane. It essentially tracks all the sequence numbers you see on ticket faces.
Saying that, there is LENNON reference data which you can download via SFTP but it's mostly useless.
The LENNON replacement programme is being worked on at the moment but I haven't heard any details of what will come out of it yet.
As a side note I went to the NRS replacement (RARS) day last week and it looked quite good. I meant to do a write up here but haven't had the time.
Cheers,
Linus