Commuter option

Hello all. Apologies if this has been asked and answered recently, but I couldn't see anything similar. Currently commuting to work (20-25 miles round trip) and looking for some new wheels to do it on. However, very limited budget (in bike terms) of £500, and that's the absolute max. So was wondering if anyone had any suggestions. Noticed the lower end of the Specialized Sirrus range scrapes in under the mark, but I know next to nothing about road bikes (transferring from MTB) so I don't know if there's better value for money out there. Anything in particular I should be looking for, or avoiding?

Thanks,

- Andrew