Guardian Care Homes has changed its advisers for the second time in two months in a major dispute against Barclays, seen by many as the test case for Libor manipulation.

The care home operator's owner, Graiseley Investments, yesterday (4 February) instructed the London office of US firm Hausfeld, just two months after the Wilkes Partnership was bought in to replace litigation boutique Cook Young & Keidan (CYK) as advisors.

Hausfeld London managing partner and former Slaughter and May associate Anthony Maton and partner Lianne Craig have taken on the case for Graiseley, understood to be on a no-win no-fee basis. The firm is already active in a number of Libor-related suits in the US.

The dispute – Barclays Plc v Graiseley Investments & Ors (Guardian Care Homes) – has seen care home provider Guardian attempt to sue Barclays over the alleged mis-selling of interest rate hedging products, known as 'swaps', that the company claims has cost it millions of pounds since 2008 based on manipulated Libor rates.

The case is set to be heard in April and is being closely watched by small businesses which have been sold swaps on the basis they would be protected against interest rate changes.

Legal Week understands one of the issues with the instruction to date has been the huge amount of material disclosed by Barclays, which require larger numbers of lawyers than those available to boutique litigation teams.

"I think it's a confusing choice; Hausfeld may be taking it on a fairly uncommercial basis," commented one senior City banking partner, who has advised clients on potential Libor-related claims.

"The claim's quite a difficult one, and my inkling is that Guardian wants to rip up the swamp, but there's every chance they might get damages."

When the Wolverhampton-based care company first brought the case in 2012, it turned to CYK co-founder Philip Young, alongside Brick Court Chambers' Tim Lord QC and Farhaz Khan from Outer Temple.

In December, the company drafted in the Wilkes Partnership's Andrew Garland, who instructed Bristol set Guildhall Chambers' Stephen Davies QC, alongside John Virgo and Neil Levy, for the trial. Guildhall will continue to act alongside Hausfeld.

Barclays is being advised by Clifford Chance, with litigation partner Ian Moulding in the lead role. The magic circle firm instructed Adrian Beltrami QC and Richard Hanke from 3VB as counsel.

In the US, Hausfeld has already filed a number of class actions around Libor rate-rigging, including cases on behalf of the Mayor of New York and the City of Baltimore Council.