Partnership dispute

[A Monsoon]

Hi there, I'm trying to help a friend of mine. He was in an unincorporated business partnership until 8 June 2012. The partnership was profitable every year. However, when the accounts were drawn up in January, 2013, they left him owing the partnership £19000. Although he did ask questions about it, the partners didn't respond and he consequently didn't sign the accounts. So now it is coming up to 6 years this Friday, they ex-partners are now chasing him for the money. They left voicemails and want his new address to send papers. Will it be a CCJ or a letter before Action? Can he have the debt statute barred and from when does the time limit start? If he pays the CCJ, will the CCJ be removed instantly? Does anyone recommend any partnership solicitors?