Sea Slug was the only contender for its requirement.
Here is a brief timeline of RN SAM projects.
1944-47 Fairey works on Stooge - a small mini aircraft-type missile with 4x 3in boost rockets (probably 3in RP motors) and 4x Swallow sustainer rockets and guided visually via radio link, subsonic and too slow to be of much use.
Ben - originally a land-based design with photoelectric guidance, launched from a rail on a radar-directed searchlight, the 3in RP motors lacked range so the Navy looked at a liquid rocket engine with solid boosters. Was meant for destroyer sized ships.
1944 LOP/GAP - a merger of the Brakemine and Ben projects with the Lizzie rocket motor and 7x 3in booster rockets for supersonic speed and ceiling of 40,000ft. Out of this grew Sea Slug, the first mention of its name being in 1946. LOP/GAP was the grandmother of all subsequent UK SAM development as the RTV.1 test vehicle.
In 1949 the Stage programme of SAM development began for land-based SAMs. Later, Stage 1 3/4 was Bristol's Blue Envoy, designed to intercept Mach 2 bombers and intended for land and sea use. It had a double delta wing, 2x 18in BRJ.800 ramjets and four booster rockets to reach Mach 3 and a 200 mile range. It would be constructed of stainless steel to resist the aerodynamic friction. Being 26 ft (8m) long and 16.4ft (5m) span it was too big for most warships and required assembly before launch, cutting rate of fire and its minimum range of 10 miles was too close to the radar horizon. In was cancelled in the Sandys cuts of 1957.
You could use Green Flax, aka Thunderbird Mk.2 as used by the British Army 1963-76. It was briefly considered during 1956 as an alternative to Sea Slug Mk.2 but rejected due to insufficiently powerful illuminators and lack of resources.
NIGS began in 1958 as the Sea Slug successor.
There were plenty of smaller short-range naval SAM projects.
1948 Popsy A - grew out of Ben, subsonic, semi-active Q-band seeker for use against weapons like Fritz-X, Hs-293, Blue Boar.
Popsy B - a supersonic version, planned for service in 1957 and able to deal with aircraft too. Used same seeker. In direct competition with the Direct Acting Close Range gun mount. An interesting feature was that both designs could be bolted to merchant ships and guided from escort warships. Both Popsy variants were cancelled in 1950.
Mopsy/ Mopsy Meteor - joint UK/US programme using US Meteor AAM airframe with the Popsy seeker head. Again could be fitted to naval and merchant ships.
1953-57 Orange Nell - designed to intercept supersonic missiles, max range 5.7 miles and minimum range 1.1 miles. Mach 1.2 speed and a 'warmed-up' reaction time of 10 seconds. It was to be guided by an S-band volume scanning TIR and an X- or Q-band illuminator. It could be looked on before launch or acquire after launch, would have a 100lb HE-frag or continuous rod warhead. The twin-rail launcher would replace a 5in turret and the magazine consisted of two concentric rings totalling 40 missiles. The missile had 4x booster rockets. The likely miss distance of 20ft might damage a missile airframe but the warhead might survive and since destruction was not assured it was decided to go back to the idea of destroying the bomber before it could release its stand-off weapon. It too was cancelled in 1957.
Then along came Sea Cat as a private venture, trialled 1962 and acquired. In 1962 Shorts revisted the Orange Nell concept and designed Sea Cat II but using the same launcher. The same year the Confessor study began, in 1967 the BAC PX.430 was selected, later to become Sea Wolf.
I had drawn most of these some time ago, lack of info on the launchers is a pain but I guess some educated guesses could be made. Hope this info helps though, even though the choice is not wide.
English Electric Canberra FD
Interwar RN Capital Ships
Never-Were British Aircraft