I ordered the "Lucas" battery from MDS on Sunday and it arrived today. Except it isn't a Lucas. Its a "Numax" Close examination of the web page does refer to the manufacturer being Lucas/Numax.
I called MDS and the guy said they would take it back if I wanted but that they are the same battery from the same factory. It certainly looks identical to the Lucas one in the website picture.
Not sure now whether to send it back and get the Exide from Motorworks or to give it a go. What's in a name anyway?