This is a good example classic with virtually all-original equipment. It was made the year I got my first bike, so I am familiar with the equipment on it, since it was normal available equipment when I was starting out. You have a good hand-made lightweight frame in Reynolds 531 db tubing, with early Nervex Professional lugwork, made when Armstrong were still a much-respected concern (they had been going since at least the 1920s), before they were swallowed up by the TI/Raleigh empire around 1956 and the name was degraded by being fitted to badge-engineered low end clunker roadsters, as Raleigh did with most of the firms they took over (Carltons produced at the special products division being an honourable exception).
Equipment includes - Williams C34 chainset (originally chromed); GB Coureur Hiduminium brakes; Brooks saddle; Cyclo Benelux gear (-the "clo" is the last 3 letters of Cyclo) 5 speed as was the latest kit then - they also did a rod-operated front changer and the Williams C34 could be had with double rings. You would need a longer bb axle for a double); Weinmann alloy rims (on possibly Bayliss-Wiley hubs ?); Bluemels mudguards (aka fenders in USA); stem, bars, seat pin and quill pedals also correct original. The little "ping" bell probably came a bit later, but I had one about 1957 so it would count as a kosher period owners retrofit (it has lost the hammer arm part from the actuating lever). Even the little cable-tidy is correct for the period.
The frame is certainly worth cleaning up and respraying as original - (try http://www.gracesguide.co.uk/Armstrong_Cycles
for transfers). Reynolds 531 is as tough as they come, and this frame looks in pretty good condition. The alloy equipment and the spokes have suffered from corrosion. The alloy may clean up. The spokes need to be junked for safety and aesthetic reasons, but chrome double butted was available at the time and modern chrome or stainless would look correct on a refit. The hubs will probably clean up and the hubs, bottom bracket and headset should be mechanically sound unless the cones were overtightened - they need dismantling, cleaning and re-greasing. The gear may well clean up (the little wire loop seen by the bottom of the arm on armweb5.jpg is the end of the tension spring, and should be rotated clockwise and into a slot on the end washer to increase spring tension). I would expect the freewheel to be original - probably a cyclo benelux item. This should clean up, and probably needs lubricating - be careful if dismantling, it is full of fiddly tiny parts and ball bearings. The opening lockring is left-hand thread by the way, though the freewheel screws right hand thread onto the hub.
Congratulations - you have a fairly rare and good quality frame (I have the previous model with the Ekla Sandcast lugs, which is now a bit rarer, but is performing good service built up into a bike with new equipment. These early lightweights were built to give excellent service for years, and their quality still shows. Have fun restoring it.