100% scam.
While the website could be legit, that "owner" is a scammer and there is no condo/house/apartment for rent. Any phone number that starts with +44-70 or anything similar is not based in the United Kingdom. It is from a UK based cell phone redirect service that can be answered by anyone anywhere in the world. It is a favorite service of scammers who want to pretend to be in the United Kingdom but are really half way around the world from there.
There is only a scammer trying to steal your hard-earned money with stolen pictures of someone else's dwelling and a fake story of being out of town/state/country doing charitable works.
The next email will be from one of the scammer's fake names and free email address and will demand you pay for first month's rent and deposit, in cash, and only via Western Union or moneygram then he will "ship" the keys to you.
The scammer might suggest you "send" money to a friend or to yourself and then send a scan of the receipt to the scammer as proof you have the funds. The scammer will simply that take scanned receipt or just the MTCN# (money transfer control number) into Western Union or moneygram store and pick up the cash you thought you were sending to a friend or yourself.
Western Union and moneygram do not verify anything on the form the sender fills out, not the name, not the street address, not the country, not even the gender of the receiver, it all means absolutely nothing. The clerk will not bother to check ID and will simply hand off your cash to whomever walks in the door with the MTCN# and question/answer. Neither company will tell the sender who picked up the cash, at what store location or even in what country your money walked out the door. Neither company has any kind of refund policy, money sent is money gone forever.
Now that you have responded to a scammer, you are on his 'potential sucker' list, he will try again to separate you from your cash. He will send you more emails from his other free email addresses using another of his fake names with all kinds of stories of great places to rent, lottery winnings, millions in the bank and desperate, lonely, sexy singles. He will sell your email address to all his scamming buddies who will also send you dozens of fake emails all with the exact same goal, you sending them your cash via Western Union or moneygram.
You could post up the email address and the emails themselves that the scammer is using, it will help make your post more googlable for other suspicious potential victims to find when looking for information.
Do you know how to check the header of a received email? If not, you could google for information. Being able to read the header to determine the geographic location an email originated from will help you weed out the most obvious scams and scammers. Then delete and block that scammer. Don't bother to tell him that you know he is a scammer, it isn't worth your effort. He has one job in life, convincing victims to send him their hard-earned cash.
Whenever suspicious or just plain curious, google everything, website addresses, names used, companies mentioned, phone numbers given, all email addresses, even sentences from the emails as you might be unpleasantly surprised at what you find already posted online. You can also post/ask here and every scam-warner-anti-fraud-busting site you can find before taking a chance and losing money to a scammer.
If you google "fake apartment rental", "fraud Western Union house rent scam", "fake craigslist apartment rent scam" or something similar you will find hundreds of posts from victims and near-victims of this type of scam.