Read this string before making any decision...
http://forums.moneysavingexpert.com/showthread.html?t=1324209
Also details on 2 different Suprima 60 boilers below...
Potterton Suprima 60L
Fuel Type Gas
Boiler Type Conventional
Method Non-Condensing
Flue Type Room-Sealed
Fan Fan Assisted
Output (kW) 17.6 - 17.6
Manufactured From/To 2001 - current
SAP seasonal efficiency 78.1%
Potterton Suprima 60 HE
Fuel Type Gas
Boiler Type Conventional
Method Condensing
Flue Type Room-Sealed
Fan Fan Assisted
Output (kW) 17.72 - 17.72
Manufactured From/To 2004 - current
SAP seasonal efficiency 86.2%
Peccavi
March 2009