Now that I have the Peter Marland article in front of me a few additional details.
Type 984 began as 'Project Postal' in 1947, designed early 1950s and a complete development model completed in 1955, installed in HMS
Victorious in 1958. Marland puts the 984 with CDS and DPT as being about 5 years ahead of the USN.
Type 985 - a second generation set, experimental work 1956-60. Concepts studied included "frequency scanning, travelling wave tubes, phased arrays, multiple pulse-forming circuitry, and other techniques." Prior to the project definition phase it was replaced by Project 988 'Broomstick' in 1960 (itself cancelled in 1968).
NSR.7938 - Type 1015 for a new long-range radar [note that this designation was in the IFF numbering sequence for some unknown reason! It should probably have been 989]. Dual frequency UHF (430/600MHz) with back-to-back or wrap-around antennae to remove need for a masthead location. Studies included 'Broomstick', SPS-52 and three UK designs from EMI, Plessey and Marconi. Later studies included a modernised Type 965, SPS-40B, LW-08 and Selenia SPS-68. Cancelled in late 1971.
[The ASWE report I found at Kew - ASWE Laboratory Report XRA-63-5 A Study of a Proposed Radar System Employing Within-Pulse Electronic Scanning over 360° - dated August 1963 using a cylindrical array must be connected with this.]
There is no mention of 'Trackwell'. There is mention in the article of a Type 983/983 replacement for fighter direction in 1953, described as a "mini-984" with a V-beam. Since 'Trackwell' doesn't seem to need a 992Q TI radar its possible its an outgrowth of this 'mini-984' concept?
In all there seems to be a sense of confusion and overlapping work and the more we dig, the more we find a lack of concrete developments. It feels like when NIGS/985 were canned in 1960 in favour of newer missile and radar technology, that they were perhaps another 5-10 years away from operation. They were becoming superseded but certainly the overall radar development picture (
see here for more on the Marland article) is one of downgrading, chopping, cancellation and losing the lead to US, Dutch and even Italian competitors. There does seem to have been a mismatch between the systems and the ships, really there should have been integrated development.