The code signing key used for BT747 had to be upgraded to SHA-256.
Unfortunately that also revoked the old key and apparently the timestamping was not properly done with the previous signatures. So the java laucher complains that the certificate is revoked.
All files have been resigned and republished.
You may need to launch:
javaws -viewer
[on windows : "Windows Key + R" to access the execute popup where you can enter this].