budget speakers for Musical Fidelity A300 ?

You're going to get lots of suggestions and most of them (if not all) will suggest terrific speakers. One brand of speakers that makes a line in that range is Triangle. Check out reviews in Stereophile for information. I'm not suggesting because the reviewer likes.them you ought to but you may find their product line of interest.

Excuse any typos but I'm writing this on my (not so) smartphone while on the train to work.

My friend... I suggest a pair of Vandersteen 1c speakers --- or a used pair of Vandersteen 2c speakers. Both are wonderfully full-bodied, play well at low volume, are, for the money, really, really, really good. The vandersteen speakers at this level compete mid-level with speakers at nearly three times their cost. Great value and wonderful, full range capability. Both the 1c and 2c are so good because they have no real flaws (at that price point). That is, the whole is better than the sum of the parts... no glaring weaknesses (and, almost everything else at that price point does --- some will have an attribute or two that exceed those for the Vandys... but have mixed in flaws the Vandys do not possess.) To me, this is a no brainer... anyone in this price range needs to hear the Vandersteens

At under $600, you will do very well looking at the classifieds (monitor) listings here.

One recent listing that stands out to me, is the Neat Motive 3s listed. I use Neat Critiques with a Rega amp and find the Critiques wonderful speakers. According to Bob at Neat Speakers, the Motive 3 is the current offering most like the Critiques. They should do well with you eclectic tastes.