Retiring under a collective settlement agreement will not affect your entitlement to a top-up. Top-ups are paid on all pensions that are claimed without a rate reduction and are added on automatically by age 55 at the latest for claims in 2021. Top-ups are paid on pensions claimed at age 60 or later if the member has accrued a minimum of 20 years to their career.
Your pension will then be topped up until you reach statutory retirement age under the basic scheme, as determined by your birth year (currently 62 years old).