AH-64E ZM717 was read (as were all but ZM702), and the hex.code is confirmed as 43C93F. It is possible to read the serials (just) from about a mile away when parked on the flight line in the mornings. If on westerlies, they land in front of you if you're on the road east of the base. There serials are easy, and photography will yield good results. It seems 4 AH-64Es outside on any given day is standard proceedure.
The Apache cafe at the museum offers a view onto the base, but not the 673 Sqn area. Wi-Fi is available in the cafe, so you can monitor ADS-B whilst taking a break. The cafe closes at 16:00.
A further AH-64E was flown from Wattisham to here on Thursday 01st December in the shape of ZM721 using callsign AAC313.
This gives the resident 673 Sqn a total of 9 airframes, but AH-64E ZM715 has not been recorded as flying since the 15th September. This according to ADS-B.