Tiffin boys only test VR/NVR.
For VR, I suggest you look at Patricia's post.viewtopic.php?f=3&t=30178
For NVR, we did Bond How to do NVR I believe AE book is also good), followed by Bond assessment papers to Book 5, Athey, AFN, Learning together.
This was followed by GL and few other practice/test papers, but don't start the pratice papers until just 3 months before the test (May/June). First concentrate on mastering the techniques for NVR question types. Then do the practice papers. NVR can be done very quickly so don't panic and don't start test papers too soon.
NVR types for Tiffins exam are here.viewtopic.php?f=30&t=12305
Hope this would be helpful to you.