Me and my significant other have decided it's time to take the plunge and get a dog. We both grew up with dogs (She grew up around staffies and I grew up with dobermanns) However, we are both in love with the Boxer breed. The one issue is we have a relatively small place (1 Bedroom ground floor maisonette) we were wondering if anyone has experience with boxers in this kind of setup and any tips when it comes to being first time owners.

That, I suggest, would depend on a few situations like for starters, whether the pup would be spending long times during the day alone = making noise others might hear.   Secondly whether you have your own private (contained) outside space to use until the pup has had all his vaccination shots.   And finally whether you have some good walking areas near where you currently live.

I dont know if you've made arrangements to buy yet, but, both parents must be hip scored for later in life HD (hip dysplacia), for boxers the score of both parents
should be lower than 14.4, make sure you see both parents documents on this, if they dont have them don't buy, black & white issue.

As a large heavy breed early puppy exercise should be just very short walks early on a few times per day to let the joints mature without 'stressing' them'.

Some health guidlines below.
http://www.dogbreedhealth.com/boxer/
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Dogs need your time and they need sufficient daily exercise.  But they are not going to get that daily exercise on your property unless you live in a country house with its own grounds!!  If you are taking your dog out daily for exercise, it doesn't really matter how large your living area is.

As others have said it depends what sort of owners you would be rather than how big your house is but you don't mention a garden which I think is a priority for housetraining and restricted exercise which puppies should have before they start on the bigger walks.  Boxers are IMO some of the most energetic and bouncy puppies and pretty hard work as youngsters, do look into heart testing as cardiac problems are quite a big thing in the breed, I would not consider buying from anyone who does not do the testing recommended. Buy in haste and repent at leisure is very apt for these lovely dogs.

Read up on health tests on the boxer breed council web page and ensure all of those suggested are done and clear.
My friend has a dog, albeit not a boxer, in a flat but it just means she has to make extra effort to take the dog out for toilet trips as she can’t just open the garden door.
Consider crate training; done properly it’s a godsend. We took our one year old pup camping this weekend and he went straight into his crate at night to sleep. It also keeps pup safe when you aren’t about.
I’m on my second boxer pup and I would say they aren’t really any more lively than other similar sized puppies. They aren’t usually vocal dogs but there is always the exception to the rule and this certainly needs to be considered in a flat.
They are a fun breed that should relax in the home but once adult and fit will take as much exercise as you can give them. Mine haven’t been thick as such but they are not going to make obedience competition dogs!

I agree with the above replies.
It doesn’t matter the size of the property it’s how you’ll deal with exercise and boredom.