LONDON -- Standard&Poor's CreditWire 4/8/97 -- Standard&Poor's today raised both the claims-paying ability rating of Eagle Star Insurance Co. Ltd. (ESI) and the financial strength rating of Eagle Star Life Assurance Co. Ltd. (ESL) from single-`A' to single-`A'-plus. The upgrades in part reflect a change in Standard&Poor's rating methodology which has affected the credit given to the Eagle Star companies for the implicit support provided by its parent, B.A.T Industries PLC (BAT). S&P believes that Eagle Star is strategically important to BAT, a U.K.-based international tobacco and financial services conglomerate, although continuity of the rating at this level is dependent the rating of BAT (rated single-`A'-plus/`A-1'/negative). On a stand alone basis, the companies have