Email- Third Party Info'

My question involves defamation in the UK.

Hi everyone.
Bit of a complex situation. So im hoping i list events , and circumstances as detailed as possible.
Several characters involved, although couple are loosely on sidelines.
Lets call them, Guy 1-4.
Guy 1, is a supplier of items, resident outside UK, but visits UK to carry out his business.
Guy 2, allows Guy 1, to stay at his house, then alledges that while hes out , Guy 1 upsets his wife.
Guy 2 goes on some what of an electronic rampage, and sends third party information, in emails, and private messages. (Through forums connected to suppliers interests,and loosely business)


Guy 3, sent a deposit to Guy 1, around 10 months ago.
Guy 4, received deposit, on behalf of Guy 1, and received emails from Guy 2,
which included emails from Guy 1, 2, and 3, and other emails, from other party's.

Guy 1 is alleging, that Guy 2, "Intercepted" emails, that he included in his rampage, and is in breach of the Data protection act, so is taking court action, for Libel.
Guy 1, has also stated, that Guy2, was Slanderous, in saying that Guy 1, had spent all of Guy 3's deposit.

Guy 4, had forwarded , 2/3's approx, of deposit from Guy 3, to guy 1.
Guy 4, had also forwarded payment for articles, that Guy 1 has not/ could not supply.
Guy 4, told Guy 1, to use that money for remainder of Guy 3's, payment.

Guy 1, is now asking Guy 4, for the emails from Guy 2.

Whats that saying.....???...Oh yes, never work with Animals, and Children..... Working with "Adults" seems complicated enough in comparison!!

Anyhow, main question is, if Guy 2, is indeed in breach of any Data act, wouldn't Guy 4 be in breach also, for forwarding emails, without the consent of the mails included from Guy 2?

If anyone could advise of this, and the rest, i would be extremely grateful. As would others involved also.
Truly, many thanks.