As far as I remember, the band were awarded with a golden record for 250.000 copies of T&C sold in Germany in 1998.
In the booklet of the "New Model Army the collection" Emi cd released in 2004:
"NMA have undertaken an eventful 24-years journey that has seen them sell millions of records at home and become huge in Germany"
"Millions of records" in the UK?
About "Thunder and consolation":
"A top 20 album in Britain, it also spawned three U.K. Top 40 singles and sold over 250.000 in Germany"
It seems that "Thunder and consolation" and "Impurity" were NMA's best selling albums in the UK and Germany (and worldwide?)
I guess that the EMI years from "No rest for the wicked" to "Raw Melody men" included were the most commercially successful times for the band, but if i remember well "the love of hopeless causes" also did pretty good in the UK charts.