Unpaid work outside contracted hours - do I challenge this?

[PeterPeterson]

I am going to try to keep this vague so I don’t get outed but I also don’t want to drip feed. I work in retail banking, I am salary paid (18.5k per year) in my contract it states that I work a 35 hour week and my hours are Monday to Friday 9am to 5pm with some Saturday’s as required by the business, my contract is not Saturday inclusive which means I can be paid extra for the hours I do on a Saturday (not have to take as TOIL) and for example if I ever did do any overtime (worked till 6pm one evening for team meeting etc.) I would be paid for it.
My question however is this, my colleagues and I, in my branch as well as all other branches of our company are expected to put the tills on and prepare the branch ready to open at 9am, if our systems aren’t set up for 9am we will get a report from our head office asking why. We arrive at 8.45 to do this. Then we are also not allowed to close down our systems or take the tills off until after 5pm when we close (if we take them off early, another report asking why). This means on a good day it is usually 5 past 5 by the time we have counted cash and put it away and are able to leave the branch. This has been the way since way before I started, but we do not get paid for this time.
Recently the company recognised that this was causing a bit of upset with branch staff and offered two hours of TOIL to each colleague in branch each week however this hasn’t quite gone to plan and has now been revoked.
As the company now recognise that we are effectively working an extra 20 minutes each day 5 days a week, do I challenge this and ask what they are going to do about it? When I work out how much extra over the 4 years I have worked there that this works out to be pay wise it is quite a shock, but legally I don’t know what I stand with it.
Any opinions or advice is really appreciated.

I’d check your contract. We don’t get overtime and ours state how many hours per week, report to work by 9am and subject for a lunch break of one hour to continue to duties until 5 or such later time as the company requires however in busy periods you will be expected to be flexible.

I doubt many jobs enable people to be in bang on the start time and leave exactly say 5pm.

In answer to a couple of questions, I don’t get any additional breaks to cover this, we get an hour unpaid lunch so are there say 40 hours a week but accounting for lunch we are contracted to 35.
In theory someone opening and finishing early and someone starting later and staying to close works but practically there are a few problems with this, we have a safe working limit of two people, so we must always open and close with two. There are only 6 members of staff in my branch (we’re a smaller branch), my branch manager and I are the only full time members, everyone else is part time. This is common place in my company, we have very small branches with a big emphasis on family friendly roles.
After taking a look at my contract, discussing it with members of my team and discussing it with other colleagues in my area I have raised it with our HR department and am waiting to see what answer they come back with.
A point I raised with them and they agreed with on the phone is that I pay for my DD to go to a breakfast club at school each day, so that I can arrive at work at 8.45am, however her school is close to where I work and starts at 8.45am. If I were to say drop her at school at starting time I would still make it to work a few minutes before 9am ready to start my day IYSWIM, therefore I’m not being paid for this 15 minutes before my contracted start time but also effectively loosing out on my own money by having to pay out for childcare so I can be there for 8.45am.

When I had a customer facing job we got in at 9 to open up at 9.30. However, we didn't get paid beyond 5pm but we were generally able to close everything down so we were certainly out the door by 5 past 5.

Shops do this too. If you want people to stick around after closing, pay them. Why should people do unpaid work?

The idea of having some people come in at 8.45 and others leave at 5.15 is a good one.

For a full time worker, an extra 20 minutes a day will amount to two weeks unpaid work a year.

Absolutely agree. I have worked an extra 25minutes per day over the last 5years for no extra pay. Recent changes will also mean a large increase in workload, I will struggle to finish on time most days which impacts on family life. It also impacts on myself mentally as work that’s outstanding is hanging over me