I owe SALMO an apology for misunderstanding his reply to my O.P. Those slidy bits (and as explained further above by CooperMan) do indeed permit the hood securing prongs to take-up their correct position. This may be one of those "secret features" that relates to the other posts on the subject of getting the rear of the Easy-Up hoods into the correct position. My hood now fits better than ever, fore/aft and laterally, on both sides. And the hood release lever now does its job properly (with the downward pressure on the rear of the hood to help matters along). The only tool I required was a 4mm allen key cut-down to about 9mm on the short arm to enable me to get to the slightly-sliding securing bolts.
"Thinking and manipulating time" was about an hour, so that's saved me a heap of dealer charges.
