Explain Index Linked

[bill.advanced]

Basically if 2 FF retired on the same day same rank same pay, one at 5o and the other at 55 they would be on the same take home pension. The 55 year old would get a rise every year and the 50 year old nothing until 55. BUT because the % rise is effectively "banked" for the 5o year old at 5 years of retirement 55 & 60 their monthly pension would be the same again because the younger one's pension would effectively catch up.
The younger FF would NOT get the back pay only the back rises
This is all because "normal" retirement age is 55. Even with 30 years service the 50 year old is technically taking early retirement.

That sums it up perfectly stressed.

[SoCo]

Not to sure exactly what you mean there Soco, but your first years rise is a proportion of the annual rise based on when you retired.
IE you retire January so you would be due 3/12thrs of whatever the annual figure was as a rough guide.
If the annual rise was 2% you would only get 1/2% rise in April.

So if a FF retired in February their pension would not increase by the full 1.7% (Sept CPI) in April.

[bill.advanced]

So if a FF retired in February their pension would not increase by the full 1.7% (Sept CPI) in April.

No their rise would be a proportion of that 1.7% based on their retirement date.
The April rise is based on the previous sept cpi.
If you retired in February you would receive roughly 2/12ths of the 1.7% rise.
Your first full cpi increase would not happen until April the following year.