The British Army deployed a range of anti-tank guided weapons in 1979. The most numerous of which was the wire-guided Swingfire.
Swingfire earnt it's name from the capability of being able to launch up to 90 degrees from it's intended target. The missile would literally 'swing' into it's victim. In addition the weapon could be fired remotely from up to 100 metres from the missile platform, giving it immense tactical advantages in the use of cover and concealment.
The missile was large, heavy and expensive. It was found mounted on the FV438, a variant of the FV432 armoured personnel carrier, the CVR(T) family FV102 Striker and the FV712 Ferret Mark 5. The FV438 deployed two missile launchers that could be reloaded from within the vehicle. The Striker had five externally loaded launchers and the FV712 Ferret had one mounted on either side of the turret.
The FV712 Ferret was withdrawn from service at the end of 1978, to be replaced by FV102 Strikers. The Strikers then equpped Royal Horse Artillery (RHA) guided weapons batteries. Several FV712 still exist in private hands today, so would have been available again quite quickly in 1979. The smaller size and greater road worthiness of the vehicle may have made it more practical in the Winter of '79 than it's larger tracked brethren.
A variant of Swingfire called Beeswing could be mounted in Land Rovers and there was an interesting sub-development called Golfswing which was a single missile launcher pulled by one man on a golfer's style trolley contraption. You can see enormous potential within Winter of '79 for this! Whilst it may seem a bit Heath Robinson and somewhat of a joke, it was designed to emulate the 'Suitcase Sagger' which had been seen to be effective against Israeli armour in the Seven Day War as recently as 1973. After which western military pundits advocated a network of man and motorcycle portable guided weapons as an answer to the tank armies of the Warsaw Pact. this would ultimately lead to the adoption of the MILAN wireguided anti-tank missile.
Swingfire had a range of 4,000 metres and would prove to be an excellent tank killer. Anecdotal evidence suggests that it was successful 75% of the time through malfunction due to poor handling, storage or even something as simple as the wire guiding it becoming caught or cut during the missile flight. It was also a complex weapon to learn to use, and so had a built in operator training facility within the sighting and operating unit. In wargames terms, I suggest treating any unit that's new to the weapon as Novices when firing with a corresponding reduction in hit probability.
In 1979 the Swingfire armed FV438s and Strikers were controlled by the Royal Artillery and operated in dedicated Guided Weapons batteries.
FV438 is not currently available in 20mm/1/76th scale. The sexier Striker is available from RH Models, (code BAFV19), Kingfisher Models (code MAC-114) and the FV712 Ferret Mk5 is unsurprisingly available from BW Models (Code Fv309).