[CR]Dating a 1980s Raleigh Corsa

I have had several enquiries regarding the age of the Raleigh Corsa frameset I have listed on ebay at http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem <http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&rd=1&item=7219332207 &ssPage Name=STRK:MESE:IT> &rd=1&item=7219332207&ssPageName=STRK:MESE:IT , some suggesting that it is earlier than the mid 80s I thought. (In which case bringing it neatly on topic!).

The frame number is B15266 stamped on the underside of the bottom bracket. I presume, therefore, that it is not 80 or 81 Worksop built, and it does not have the letters associated with an Ilkeston build, although one correspondent has suggested that there are build similarities with the Ilkeston frames. There is also what appears to be a serial number on the decal below the 531 decal, which is 03586540.

Do any of the above numbers make sense to any list member, and so allow me to give those interested some better information?

Peter Brown, Lincolnshire, England