BCL's 3000 Series: First choice in the Top Ten

The original BCL - Business Computers Limited - was formed in 1968 as a result of the merger of Systemation Ltd and Business Mechanisation Ltd. 

This company actually went bust in 1974 but was ressurected in 1976 as Business Computers (Systems) Limited, and eventually went public in 1981 at which point it became a PLC[source: https://www.computinghistory.org.uk/sec/9514/BCL-Business-Computers-Ltd/].

Somewhere in-between it released the curiously-named Molecular computer - an 18-bit machine - and a couple of desk-sized models called SUSIE - Stock Updating Sales Invoicing Electronically[source: https://www.computinghistory.org.uk/det/9515/BCL-Susie/], based on the Molecular.

However, by the time of this advert, the company seems to have reverted to being a reseller, as it's now selling Xerox/Diablo's 3000 system - a multi-user micro that supported up to four users.

The advert's worth including for the nice use of a 1950's-style jukebox, with types of business software as the "hits". Oddly, Word Processing - which judging by all the adverts for it should be one of the most popular - is down at number 9.