Welcome, Dessmale!
I've had the best luck with a feed low in phosphate and high in potash, like the new formula Miracle-Gro--not the old one.

We use Protea Fertilizer from Trevena Cross in Cornwall (who sells Proteas).

See: http://www.trevenacross.co.uk/shop/pics.asp?plantid=618

which comes from this page: http://www.trevenacross.co.uk/shop/page5.htm

We were originally told by the Protea person there that we should "start feeding when the roots filled the pot" - although in reality we tend to just start feeding when it's been in the pot quite some time.