Question: John McCusker from Before The Ruin has toured with which guitarist from a top-selling 80s band?

Context paragraphs:
Awkward Annie: Awkward Annie is the seventh studio album by English contemporary folk musician Kate Rusby, released on 3 September 2007 on Pure Records.  The album is the first to be produced by Rusby herself, following her split with husband and producer John McCusker.

Snowgoose: Snowgoose is a Glasgow based folk rock band.  The band was formed as a three-piece with Jim McCulloch (formerly of The Soup Dragons and BMX Bandits) on guitar, Dave McGowan on bass and Anna Sheard on vocals.  Raymond McGinley (guitar, of Teenage Fanclub) and Stuart Kidd (drums, of Euros Childs's band and BMX Bandits) joined to make the band a five-piece.  The debut album "Harmony Springs" was released on vinyl (with download code) on 21 April 2012 as part of Record Store Day.  A CD and download release followed on 12 November 2012.  The album was recorded in Norfolk and at McGinley's studio in Glasgow and features guest appearances from Norman Blake, John McCusker, Dave McCluskey (of The Bluebells), and Peter Domberknowsky (of Giant Sand).

Kris Drever: Kris Drever (born 31 October 1978 in Orkney, Scotland) is a Scottish contemporary folk musician and songwriter, who came to prominence in 2006 with the release of his debut solo album, "Black Water".  Drever is the vocalist and guitarist of the award-winning folk trio Lau alongside Martin Green and Aidan O'Rourke, and has worked with numerous other British folk contemporaries including Kate Rusby, John McCusker, Ian Carr, Eddi Reader and Julie Fowlis.  Kris plays an Atkin J45 acoustic guitar.

Heartlands (Kate Rusby album): Heartlands is an album by British folk musicians Kate Rusby and John McCusker, released in 2003.  It was the soundtrack to the film "Heartlands".

Mark Knopfler: Mark Freuder Knopfler, {'1': ", '2': ", '3': ", '4': "} (born 12 August 1949) is a British singer-songwriter, guitarist, record producer and film score composer.  He was born in Glasgow but raised near Newcastle upon Tyne, England.  He is best known for having been the lead guitarist, lead singer and songwriter for the rock band Dire Straits, which he co-founded with his younger brother, David Knopfler, in 1977.

John McCusker: John McCusker (born 15 May 1973) is a Scottish folk musician, record producer and composer.  An accomplished fiddle player, he had a long association as a member of the Battlefield Band beginning in the 1990s and was later a band member and producer for folk singer Kate Rusby.  He has served as producer and arranger for artists in a range of genres and also has several solo albums to his credit.

Before the Ruin: Before the Ruin is a collaborative studio album by Scottish folk musicians Kris Drever, John McCusker and Roddy Woomble, released 15 September 2008 through Navigator Records.  The album entered the UK Albums Chart at #156 and the Scottish Albums chart at #45.  The album was originally scheduled for a May release, but was delayed due to McCusker touring with Mark Knopfler.

Under One Sky: Under One Sky is an hour-long vocal and instrumental suite composed by Scottish folk multi-instrumentalist John McCusker.  A studio album was released in February 2009, through Navigator Records.  According to a poster advertising the "Under One Sky" tour: "This large scale composition explores and interweaves the many different styles, genres and traditions at work in today's dynamic UK folk scene"

Wenlock Hill (Merrymouth album): Wenlock Hill is the second album by Merrymouth, a folk band featuring the singer/songwriter from Ocean Colour Scene, Simon Fowler, Dan Sealey & Adam Barry.  It was released on 5 May 2014 and entered the UK Official Album Charts at #71.  It features Fowler (vocals/acoustic guitar), Sealey (vocals/guitars), Barry (piano/hammond/accordion/vocals), and guest appearances from John McCusker (violins) and Chas Hodges of Chas and Dave (Piano).

Simon Fowler's Merrymouth: Simon Fowler's Merrymouth is the debut solo album by Simon Fowler (the singer/songwriter from Ocean Colour Scene) it contains six original Fowler compositions, one of those (Over My Head) being an OCS re-working.  Released on 26 March 2012, it features Fowler (vocals and acoustic guitar), Dan Sealey (vocals and guitars), Mike McNamara (double and electric fretless basses, piano, organ, percussion and guitar), John McCusker (violins, cittern and low whistle) and Andy Cutting (melodeon).

Supporting paragraphs: Before the Ruin Mark Knopfler
Answer: Mark Knopfler