Strange variant of the No80 fuze

[ABBOT1989]

I’ve had this No80 variant fuze for a while it has no markings apart from a few numbers on base. I would love to know which variant it is . The rings have a hole on the bottom of each ring on the solid area . And inside the base the core is different as you will see in pics . I would be grateful if some one can help me with identifying what fuze it is
Thanks in advance

 

[ABBOT1989]

Hi again the part in the base looks like the centre core has had the lip removed and put in upside down.