So to clarify, I had a previous flexible working agreement with exactly the same overall hours and holiday entitlement, and in the latest version, there was a fairly minor change to the core hours only. I always work at least my top up hours on the 5th day of the week that's what the business needs, I often work more, and oit of hours/at weekends/when on leave, but appreciate thats my own doing.
It's not straightforward any way you work it as it's a slightly unusual agreement, however, if I largely work 5 (shorter because of slightly reduced hours) days a week, it's not unreasonable for me to have accepted the stated entitlement as correct - when working 5 shorter days all year round, then 25 (shorter) days leave a year would be correct, whether you calculate it based on days or hours.
The simple solution is to calculate my leave on hours alone, with an agreement on how many hours equals a day given the number of hours in a working day varies in my case.
My issue is that HR haven't acknowledged an error on their part, though it may not even be an error depending on what the HR person who prepared the agreement had in mind regarding the flexible hours/days. They, and indeed the whole HR have left in the interim, so who knows. It seems a huge, yet basic oversight for a HR professional if it wasn't their intention. It isn't as if the paperwork was for a reduced leave allowance and someone forgot to update the system and so it let me book more leave than I was contractually entitled to, which I would have noticed and flagged, this is a case of them retrospectively trying to change the binding agreement (that HR put together).
Likewise, it's not as if they have apologised and made a proposal for a change with some explanation. They are seemingly trying to calculate based on the days of the agreed core hours alone, not taking into account that I don't only work those hours or only work on those days. They seem to be suggesting I work 4 days so lose 20% of the leave allowance, but actually, I (officially) work 85% of full time hours, with a commitment to fixed hours on 4 days, but I am always working in some capacity, but for a varying number of hours on the remaining weekday.
If they had come to me with a suggestion as to what they think a "normal" or "average" day is in hours, and calculated my leave based on hours alone so I end up with a reasonable compromise in terms of numbers of days, with a mention that it was an iversight on their part and an acknowledgement of the inconvenience to me since my plans will have to change, I'd be annoyed but amenable, however, they haven't. They seem to be implying I've done something wrong, which I haven't.
My paperwork is very clear, I am entitled to 25 days with my current working arrangements. The agreement covers a set of specific items, including leave, and for everything else the original contract applies, though that also makes no referenc to pro rata for those not full time, though I would of course assume this was the case, had my separate agreement not stated an alternative provision.
I think I'm mostly annoyed at how they are handling things - if a mistake was made, it was a HR mistake.
I guess if they insist on trying to vary the agreement, they'll not have considered that I'll then work to rule and they'll lose all cover on the 5th day and at weekends, and I won't check in on days off to try and cover since we are a small team. I'll also take sick days when I'm unwell instead of just powering through and working from home, and I won't juggle anything at home to accomodate anything above my contracted hours. Ironically, I'd probably have more time off! I've told HR I'll discuss when I'm back at my desk on my supposed "non-working day". Couldn't make it up. 🤣