True, but they should still separate the roles of Employer & Trustee, even though it is the same entity acting as both. As you said it would have to be a very extreme case indeed - plus they'd also have to ensure they're not breaking general trust (or other law).
The Trustee pursuant to the provisions of the Arbitration Acts, 1954 to 1998, may refer all disputes and differences arising out of the Scheme to arbitration. Complaints of maladministration and disputes of fact or law in
Group Retirement Plan Declaration of Trust and Rules of the Scheme
relation to the Scheme may be referred to the Pensions Ombudsman in accordance with the provisions of The Pensions Act 1990, as amended, and any regulations made thereunder.
In respect of the Scheme, the Employer and Trustee shall act in accordance with the relevant requirements of the Pensions Act 1990, as amended, and any regulations made thereunder and subsequent amendments thereof, or
other legislative provisions or by general law which may override the terms of this Deed and Rules.