In the 1988 raleigh racers catalogue, the Elan was the top of the range (of the reynolds 501 bikes), it had a nice spec shimano exage groupset, some very trick parts, and was the same weight as low-mid range 531 bikes in the superior "raleight lightweight" catalogue.
the BB will be aftermarket yes.
i have seen them in good condition going for between £100 and £150, but obviously it depends on the time of year.
you might get nearer to £200 for it in spring/summer on ebay if the listing, description and photo's are done right. make sure you mention its one model above the "raleigh record sprint" and about 10 models above the steely low-spec Raleigh banana (which go for silly money for what they are IMO)
88 Raleigh Kelloggs Pro Tour (Reynolds 501) - owned from new
90 Raleigh Eclipse (Reynolds 501)
82 Raleigh Competition (Reynolds 531) SOLD
87 Raleigh Centenary (Ltd Edition no. 72 of 100, with gold plated Reynolds 531C frame)
88 Raleigh Esprit (owned from new)
90's Raleigh Ascender MTB (owned from new)