- Any number starting with +4470 is NOT a UK business, that’s an international redirect number that transfers your call overseas and is always used in Nigerian scams http://www.joewein.net/blog/2009/11/08/dial-44-70-uk-numbers-for-international-fraudsters/
- There is NO Barry White working at that hotel. Barry White is an American singer
- NO hotel uses free @consultant.com or @hotmail.com email addresses. All emails from Harrington Hall would end in @nh-hotels.com — NOTHING else
- there is NO such title in the UK as Vacancy Department Manager, that position does not exist in any company anywhere in the UK. Another sign of a Nigerian scam is using false titles.
- that website you list is NOT the official Harrington Hall Hotel Site. Harrington Hall is an NH Hotel and this is their official site http://www.nh-hotels.com/nh/en/hotels/united-kingdom/london/nh-harrington-hall.html — as you can see the phone number is completely different than the one you were given

That hotel name has already been reported in hundreds of other job scams
http://www.419baiter.com/_scam_emails/job_scams/419_emails_harrington-hall-hotel-job-scam.html
http://www.419scam.org/emails/2010-02/11/01008243.1.htm
http://scumalert.blogspot.com/2010/06/hotel-job-scam-harrington-hall-hotel.html
http://www.icomplaints.in/froud-or-not-01848.html

The simplest rule to remember is that NO UK company will ever employ anyone they have not met. If you were not flown to the hotel for an interview before you got the job offer, it’s a scam. Besides, hotel workers are not considered "highly skilled" or on the skills shortage list, so NO hotel can sponsor anyone from outside the EU unless they are already working for the same hotel chain overseas at a management level. So if you do not currently work for NH Hotels, then there is no way you can work for them in the UK