Whether the figure of 30 bikes imported into the UK still stands is debatable. However as I own 5 of them and have seen at least 8 on sale in the UK in the past 12 months that's a third of them accounted for

However importing ain't cheap and I suspect that figure is quite plausible, and whilst the popularity for importing peaked in the late 1990s or 1997 to be more accurate (given 90% of my grey bikes Suzuki or Hondas seem to have the year 1997 stamped on their import papers) there does seem to be a bit more of an import market sparking up again as people are seeing there being something in rare collectible Motorcycles from the East that through neglect and butchery (aka streetfightering) are now a lot thinner on the ground in the UK market than they previously were ... notably I am talking about the early 80s GSXR750 and other sportsbikes from that era...
Typically we are seeing prices of 30 year old bikes head toward their list prices of new 30 years past...so there is definitely something in it as an investment if you are prepared to hold onto them for a while....and you are doing your bit to preserve a bit of motorcycling history which is no bad thing.

Ps anyone interested here is a collection of CBR750F selling on ebay. I like to make a note of what is out there, you never know. Quite a variety of prices from the crazy low price of £165 I paid to the dizzy heights of £1995 as they say somewhere in between is about right !
http://www.ebay.co.uk/cln/gsxr400man/honda-cbr750f/275912772011