Lawyers for Huntingdon Life Sciences were last week refused permission to go through the address list of all 10,000 supporters of Stop Huntingdon Animal Cruelty as well as the organisation's bank statements.
Huntingdon, which did win permission to look at cheques written by SHAC, is taking the group and a number of named activists to court, claiming that it is being harassed by the organisation.
The animal testing company which has been the focus of violent animal protests for years is seeking a permanent injunction against SHAC, which originally claimed it did not exist as a group and so could not have an order made against it. It now admits it is an unincorporated association but claims not to have members.
Huntingdon's lawyer, Tim Lawson-Cruttenden, argued in court that he needed full access to SHAC's bank accounts and the address list of all supporters to prove that they included activists with criminal records. However, SHAC argued that to hand over the information would violate European human rights legislation.
The case is expected to go to a full trial in the autumn, with Huntingdon hoping to recover costs from SHAC. Last week Mr Lawson-Cruttenden said that, from the SHAC bank statements that had been uncovered, the animal rights organisation - which set up its account as an "educational awareness group" - received around £150,000 a year.
The case continues.