While the Two Kings of the Severn don't have the crowd-pleasing obviousness of the main bore they are, infact, the most interesting and awe-filling of the bore's many features, and seeing them doesn't preclude one from seeing the bore as it races down the rest of the river. To see the Two Kings, go on one of the major Spring bores (Dates). Park in Fretherne and take the footpath to Hock Cliff (Photo from cliff prior to bore), walking down from the cliff-top east along the Severn way until you are at beach-level. You can sit on the sea-defenses and watch the bore come in (certainly in March 2007 the bore didn't get near breaching them, though at other times, who knows?).
The Two Kings appear twice in this area. From the first sea defenses you get a good view of the bore as it comes down the main western channel and hits another branch of itself coming over the mudflats further west (VR View). You can then jog down further east in time to see the main western channel flow curve back up the eastern channel of the Noose (VR View) and hit the eastern channel flow as described (Photo). This is easily the most impressive sight on the bore, building wave upon wave of chaos (Photo) until finally the bore fills the estuary and the upstream flow wins over and the Kings move north (Photo). The Noose seems a viable crossing place for the Severn as the water level is normally low, but anyone stuck on the high mudflats when the bore came through would be unlikely to survive the meeting of the Kings.
After the Kings have clashed, you have plenty of time to get back to your car and drive safely to Framilode to see the bore-proper there (you'll probably have a 20-30 min wait when you arrive), and again at Stonebench (Photo), where the bore-proper is at its most spectacular (Photo).