Wanted: Small/Medium Single Speed

So, I've finally convinced my girlfriend to upgrade from her borderline-unrideable mountain bike monstrosity. I'm going to get her a new ride for her birthday, so on the lookout for something that ticks as many of these boxes as possible - I'd rather not have to make loads of conversions etc... Doesn't need to be great cosmetically, but I want her to feel the benefit of riding something that's reasonably well-maintained.

• Single speed
  
• up to £350 budget (this does not mean ask for £350 for your £100 beater pleasethankyou)
  
• 52cm-55cm frame
  
• mudguards or allows them to be easily fitted
  
• retro racer/road stylee preferably
  
• classic upright or riser handlebar (not a deal breaker by any means, happy to sort this myself)
  
  

So, i'm not asking for much? Or am I...? There's a good handful of bikes that have come up recently that I would have jumped on aside from the size, so hoping someone has something kicking about.

Seriously, if you have something that kinda vaguely fits the bill I'd rather you asked me than didn't!