FISPACT-II version 3-00-00 (October 2015) has been released through the US ORNL RSICC as:

RSICC CODE PACKAGE CCC-836
FISPACT-II Release-3-00-00

https://rsicc.ornl.gov/codes/ccc/ccc8/ccc-836.html

Please note that licences obtained through RSICC have various restrictions. Licences without these restrictions may be obtained directly through the UKAEA.