The Greenford team have completed the installation and hopes that word will soon get around about this life-saving equipment
The Greenford team has completed the installation and hopes that word will soon get around about this...
Team is a group of persons. In your Sentence you are referring to one team i.e. Greenford team hence you should use has. If you were talking about teams the you would have used Have.
To summarized Has is used with singular subject He, She, it and have is used for plural We, they etc.
Uncountable nouns like committee, team etc are sometimes treated as singular and sometimes plural.
The Greenford team have completed the installation and hope but not hopes that--------------
or The Greenford team has completed and hopes that---------
You should consistently treat such nouns either singular or plural depending on the context.
There is no difference in meaning between the two sentences.
This is a difference between American and British English. In American English, a collective noun (that is, a noun like team or army referring to a group of people) is generally treated as a singular for the purpose of verb conjugation, whereas in British English it is often treated as a plural. Elvis Costello (Irish) famously sang
Oliver's army are on their way
which sounds a little strange to our American ears!
There are some other nice examples of this and other grammatical differences between the English dialects here: http://www.onestopenglish.com/grammar/grammar-reference/american-english-vs-british-english/differences-in-american-and-british-english-grammar-article/152820.article