Excel 4 was 4.1 without the web between the conductors. It sold for the same price per metre (£4.50) and featured reversed negative conductor (the .1 in 3.1 and 4.1) and the "Simflex" dialectric which claimed to extend the life of the cable as this material wasn't supposed to degrade the copper over time.
Sound quality was bigger and fuller in tone than the anaemic and "HiFi" QED SA wire that all the Sevenoaks shops sold by the kilometre back then. At least we used to demonstrate the difference and the 4.1 and Excel 4 (both sounded very similar in practice) had a far wider dynamic range we found.....
The remaining cable stock will be several years old now and although perfect to use, £4.50m was the original retail price.
Good wire, despite CT's demise. I think the Chord Co cables at around £6m would be the nearest commercial "audio" equivalent, although Van Damme 4mm and similar would probably be as good....