Here's Wikipedia re Blue Streak:
... Post-war Britain's nuclear weapons armament was initially based on free-fall bombs delivered by the V bomber force. It soon became clear that if Britain wanted to have a credible threat, a ballistic missile was essential. There was a political need for an independent deterrent, so that Britain could remain a major world power. The use of an American missile would have appeared to hand control to the United States.
In April 1954 the Americans proposed a joint development programme for ballistic missiles. The United States would develop an intercontinental ballistic missile (ICBM) of 5,000 nautical mile (9,300 km) range, while the United Kingdom with United States support would develop a medium-range ballistic missile (MRBM) of 2,000 nautical mile (3,700 km) range. The proposal was accepted as part of the Wilson-Sandys Agreement of August 1954, which provided for collaboration, exchange of information, and mutual planning of development programmes. The decision to develop was influenced by what could be learnt about missile design and development in the US. Initial requirements for the booster were made by the Royal Aircraft Establishment at Farnborough with input on the rocket engine design from the Rocket Propulsion Establishment at Westcott.
De Havilland won the contract to build the missile, which was to be powered by an uprated liquid-fuelled Rocketdyne S3D engine, developed by Rolls-Royce, called RZ2. ...
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Eventually the project was cancelled because of its lack of credibility as a deterrent. Some[who?] considered the cancellation of Blue Streak to be not only a blow to British military-industrial efforts, but also to Commonwealth ally Australia, which had its own vested interest in the project
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The missiles used liquid oxygen and kerosene propellants. Whilst the vehicle could be left fully laden with 20+ tonnes of kerosene, the 60 tonnes of liquid oxygen had to be loaded immediately before launch or icing became a problem. Due to this, fuelling the rocket took 15 minutes, which would have made it useless as a rapid response to an attack. The missile was vulnerable to a pre-emptive attack, launched without warning or in the absence of any heightening of tension sufficient to warrant readying the missile, if such a circumstance were ever likely. ( But every engineer and scientist had to have known about the drawbacks of liquid oxygen oxidizer from the beginning of the program. And why assume that the Reds could knock out all or almost all British MRBM's in a surprise attack? I suspect that many Atlas ICBM's were deployed above ground.-- Elmo.)
To protect the missiles against a pre-emptive strike while being fuelled, the idea of siting the missiles in underground silos was developed. These would have been designed to withstand a one megaton blast at a distance of half a mile (800 m) and were a British innovation, subsequently exported to the US. ( I'm not sure that the missile silo idea originated in UK. Can anyone comment on this? -- Elmo.) [I]However, finding sites for these silos proved extremely difficult and RAF Spadeadam in Cumbria was the only site where construction was undertaken. This was also the site where the RZ2 rocket engines and also the complete Blue Streak missile were tested. The best sites for silo construction were the more stable rock strata in parts of southern England, but the construction of many underground silos in the countryside carried enormous economic, social, and political cost.
( Shoulda thought of that earlier in the program. -- Elmo. OK, Atlas ICBM's in the USA could be based farther from population centers than MRBM's in the UK. Not as much Not in My Backyard trouble in USA.)
As no site in Britain provided enough space for test flights, a test site was established at Woomera, South Australia. Whitehall opposition to the project grew, and it was eventually cancelled on the ostensible grounds that it would be too vulnerable to a first-strike attack. Admiral of the Fleet Lord Mountbatten of Burma had spent considerable effort arguing that the project should be cancelled at once in favour of his Navy being armed with nuclear weapons, capable of pre-emptive strike. Around £84m had been spent.
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Civilian programme
After the cancellation as a military project, there was reluctance to cancel the project because of the huge cost incurred. Blue Streak would have become the first stage of a projected all British satellite launcher known as "Black Prince": the second stage was derived from the Black Knight test vehicle, and the orbital injection stage was a small hydrogen peroxide/kerosene motor. This launcher never progressed beyond the design stage.
This also proved too expensive, and the European Launcher Development Organisation (ELDO) was set up. This used Blue Streak as the first stage, with French and German second and third stages. The Blue Streak first stage was successfully tested three times at the Woomera test range in Australia as part of the ELDO programme.
Although a total of eight launches were made of the multi-stage vehicle, the French and German components proved unreliable leading to the project's final cancellation, and the end of Blue Streak. The final launch was made at the French site of Kourou in French Guiana.
So, it seems that some Blue Streaks, at least the first stages thereof, made it to Australia and to Kouru without a Belfast.