You know the figures are going to be big when places such as Monte Carlo and Malta start raising their heads in the course of a commercial court action in Dublin.

And so they proved yesterday in the case where golfing star Rory McIlroy is seeking to have the courts rule void the agreements he signed with the Dublin-based sports management agency, Horizon Sports Management.

Some time ago there was a major controversy over whether the golfer, from Hollywood, Co Down, would represent the Republic or the United Kingdom in the coming Olympics.

In the filings to the Commercial Court in Dublin yesterday, McIlroy was described as “normally residing” in Monaco, in Monte Carlo. A spokeswoman later confirmed that he had moved to the principality for tax reasons, last year.

The statement of claim from McIlroy also outlines how his contract with Horizon was, in fact, between him and a company called Gurteen Ltd, which is based in Malta.

In a letter from Horizon's solicitors, William Fry, to McIlroy's solicitors, A&L Goodbody, earlier this month, the former said Gurteen, and an Irish-registered company, Canovan Management Services, "were established for the benefit of Mr McIlroy to protect his anonymity and so that these dedicated entities could deal exclusively with the task of maximising Mr McIlroy's commercial returns for off-course activities".

The fact that McIlroy’s contract was with Gurteen has irritated Horizon, as the letter from Fry’s makes clear. It said that by including Horizon as a defendant, even though it had no contractual relationship with McIlroy, the latter had acted vindictively and exposed Horizon to ongoing reputational damage. This issue will form part of Horizon’s counter-claim for unpaid fees ($2.64 million) and reputational damage.

The letter also deals with a payment to Unicef that McIlroy says was made without his authority. The letter from Fry's says it was made against a backdrop where McIlroy was to visit Haiti as a Unicef ambassador but the visit was in danger of being cancelled because no donation had been made. McIlroy later complained and the money was returned.