Completely wrong shape, size, section, and construction for either Canberra proto or Attacker, both of which had metal construction nose cones and no radar.
I’m not quite swayed by early Javelin either, though the diameter wouldn’t be far off.

I must admit I don’t!

Edit, 60ft according to this video shot from the top, http://vimeo.com/31255399
Must admit I thought it was taller than that, apparently the original tower which collapsed was 60ft as well, http://freepages.family.rootsweb.ancestry.com/~treevecwll/steval.htm

Glad there was a happy outcome and that the panels have found a very worthy home!:)

Agree with Dave, the Swift was a brand new aircraft built to the latest airframe and engine standards of the day, but was in abundance due to hundreds being ordered and then the RAF not wishing to put them into front-line service.
As the British were using Maralinga for the Op Buffalo weapons tests it made sense to ship the aircraft out for armament proof trials, probably with all manner of other items and support equipment.

Yeah pretty much, Trebelzue existed as a civil landing ground known as Trebelzue Big Field, actually two landing fields seperated by a main Newquay road.
The RAF requisitioned the land in late 1939 and built a small two runway (third runway was planned, and a threshold actually laid down – still visible) airfield there, by late 1941 it was deemed unfit for purpose by 2OADU/ 44 Group Ferry Command, and so the construction of a new three runway airfield was commenced in Autumn 1942 just to the east.
RAF Trebelzue became RAF St Mawgan even before the new St Mawgan airfield was completed by mid 1943.
The original airfield did provide a substantial parking area for both St Mawgan and St Eval, it also provided a base for Halifax, Whitley & Horsa combinations.
The main 14-32 runway was designed to be extended in the way that it was to the NW, the smaller NE-SW runway was at one time envisaged to extend across Trebelzue and one of its runways, which if carried out would have provided another 9,000+ft runway.

The excellent P.London Aviation In Cornwall book, mentions runway extensions carried out in late1943.

It seems that both Preddanack and Portreath were devised to similar schemes and time scales, Portreath was built with four runways, so would guess Predannack was as well, interestingly the runway headings are very similar.
Don’t forget the headings were a digit out during war period, ie 13-31 was 14-32.

I don’t think I’ve got more plans than Hendon, but certainly possess some that they don’t!:)

The site plan I have for RAF Predannack Down dates from May 1944, the runways, taxiways, & all other tracks are exactly how they now appear on Google Earth.
The layout of a shorter peri track within a larger one suggests (i.e. might not necessarily be the case) that initially three of the runways were slightly shorter when first built.

Unusually the plans don’t annotate the runway headings, but using the GE ruler tool, gives these results,
Runway N-S, 01-19 4,600ft (4,100ft)
Runway E-W, 10-28 4,300ft (3,700ft)
Runway NE-SW, 05-23 6,000ft (5,400ft)
Runway NW-SE, 13-31 3,000ft
The distance in brackets is the distance to the inner peri track, also the GE ruler tool will give you the heading in precise degree.
I didn’t spend that long checking these, so advise a recheck!

RAF Predannack was fairly unusual for an RAF station in having four runways built (more usual on FAA stations), nearby RAF Portreath is another, and there is another example that escapes me right now.
I have a copy of the original c.44 plans (RSPs) for Predannack, and pretty sure it shows the four runways, I will dig out later.