Complex sentence: She then transferred to the University Royal Naval Unit (URNU) of Glasgow and Strathclyde Universities to replace HMS "Attacker", which had been called into service in Cyprus during the Gulf War.
Split into simpler sentences: She then transferred to the University Royal Naval Unit (URNU) of Glasgow and Strathclyde Universities. It replaced HMS "Attacker" in this role, which had been called into service to the Royal Navy Cyprus Squadron during the Gulf War.