The US Terrier missile had some support amongst the RN staff, but consideration was not given to acquiring it for the second batch of four ships, as the County class were "shop windows" for advanced UK technology, and it was vital for the British missile and aerospace industry to continue the Sea Slug project, to allow the development of the much improved Sea Dart missile. Following problems with the original version, a reworked Action Data Automation Weapon System (ADAWS) was successfully trialled on HMS "Norfolk" in 1970. In the mid-1960s the County-class destroyers were assets; their impressive appearance and data links, feeding off the carriers' Type 984 radar, projected effective capability during the Indonesia–Malaysia confrontation. The Mark 1 Seaslug was operationally reliable and proved useful as a missile target for the new Sea Dart missiles in the late 1970s and early 1980s; the supersonic Mark 2 version proved less effective for this. There are questions as to whether it was ever fully operational and there were problems with missiles breaking up when the boosters separated. Inaccuracy, primitive beam-riding guidance and lack of infrared homing or a proximity fuze in the Mk 1 made it of limited value. Short-range air defence was provided by the GWS-22 Seacat anti-aircraft missile system, which made the Counties the first Royal Navy warships to be armed with two different types of guided missile.