Employer wants to change working hours

[higgsy18]

As above in the title, my current employer wants to change our departments working hours, part of improving the service we give.

As a department we currently work standard 9-5 hours, with a rota where I'm required to work some evenings, currently 1 a week.

The hours proposed are half the team does a morning shift, then a swap over period for the second half of the team to cover the evening, and extended our openings to Saturday's for a full day too.

My issue is I currently car share with my girlfriend and I won't be able to do this at all with the new hours (she works in another company less than half a mile away). This will have a big impact on our expenditure a month, rough calculations of £200 a month for fuel, wear and tear and parking charges, which is a tenth of our take home, and not ideal when we are expecting to buy our first house soon

Am I being unreasonable for not wanting to change my hours? Do I have any rights on the matter at all?

[higgsy18]

I thought this would be the case, I will have to try and appeal to their better nature. If I leave my job now my chances of getting a mortgage are decreased, plus I've only been working in my field for 18 months, which again I could do with gaining as much knowledge and experience as I can from my current employers before I jump ship, bit of a catch 22 at the minute

Thanks for your help