I also think it is archaic to shut shops early on Sundays, a bit like the shops closing for half day Thursday in the small town I grew up in. I personally would welcome shops opening on Sundays all day.
However I think if you have shop opening on Sundays, this will bring in 24 hour opening on bank holidays and christmas. And I already think people going to the shops at 6am on Boxing Day are weirdos.
I wonder what retail workers think of this as well.