Delphi works very well and covers most of the modules on the car, Scantoool Direct do a dedicated LR scan tool for about £90 that covers much more than generic obd tools.
Yes their is a non return valve fitted to the rear washer, but the manual doesn't give its location but I wuold guess that it is probably in the rear door.Hope this helps
Regards
Tony
washer drawing0001.pdf
Please see attached drawing, hope this helps
Tony