OWNERS Sir Oswald Cheung and Ronald Arculli will decide shortly on a jockey for River Verdon's midsummer campaign in England. Regular rider Basil Marcus has commitments in Hongkong as he attempts to retain his title and will not be available for River Verdon's lead-up race at Nottingham on June 7, eight days before the start of the Royal Ascot meeting. ''We will decide on a jockey very soon,'' said Sir Oswald, adding: ''The engagement at Ascot depends on how he goes at Nottingham.'' The Nottingham race is over 11/4 miles and River Verdon will be racing for around GBP4,000, a pittance compared to his earnings in Hongkong. If River Verdon's connections run him in the Hardwicke Stakes, or another of the Ascot races for which he is entered, he could be ridden by Hongkong-bound Frankie Dettori. The Italian-born rider is enjoying a fine spell freelancing and impressed River Verdon's trainer David Hill with his performances in Hongkong last season. Dettori chalked up a treble at Newbury last Saturday to continue his fine start to the English season. And Irish champion jockey Mick Kinane could come into the reckoning. He is already committed to Ascot where he has rides for both Dermot Weld and John Oxx.