British guitar makers were virtually unheard of at the time, but Eccleshall was one of the first to win recognition, along with Tony Zemaitis and John Birch.

[2] Over the years Eccleshall's customers[7] included Pete Townshend, Dave Davies, David Bowie, Rory Gallagher,[8] Paul Weller,[2] Davey Arthur (The Fureys), Sweet,[9] The Cure,[10] The Levellers,[11] Peter Hook of New Order,[12] The Alarm, Echo & the Bunnymen, This Picture, The Men They Couldn't Hang, Steven Woodcock, Richard Stilgoe and Richard Digance.

In the early 1980s Eccleshall made a licensing deal with the Japanese-made brand Kimbara to make and distribute an Eccleshall-designed Stratocaster-style guitar.

Eccleshall worked with many apprentices and assistants, and trained and advised other luthiers including George Lowden[13] and Kevin Chilcott[14] throughout his career.

He claimed to have been the first to house a guitar neck's truss rod in an alloy U-channel, made the first sideless hardtail bridge for a Telecaster (without the original design's raised edges, which are intended to hold a chromed pick-up cover which hardly anyone uses), and pioneered the rectangular solid machined steel block bridge saddles which are now the standard type on modern Telecasters & Stratocasters.

He was Rory Gallagher's favoured guitar technician from 1971 to 1985,[17][18][19] rebuilding and re-fretting his battered Fender Stratocaster 18 times (and replacing the neck once), and was responsible for disabling the Strat's vibrato mechanism using a wooden block, a modification he was later also commissioned to apply to Eric Clapton's "Blackie".

His 335-style bass is a unique hollow-bodied instrument used by Eddie Macdonald of The Alarm, Peter Hook of Joy Division & New Order and Simon Gallup of The Cure.