Reuters Middle East By Abhinav Ramnarayan LONDON, May 23 (IFR) - National Bank of Abu Dhabi tookadvantage of rarity value to upsize its convertible bond issueto US$465m this afternoon and still achieve a coupon of 1%, thetight end of guidance. The UAE's second largest lender earlier today said it wouldlook to issue a US$350m convertible bond with a yield of1.0%-1.5%, with a US$35m upsize option an…