Lawyer wanted to help draft complaint about Trustees of pension scheme

I require legal advice over a complaint I wish to make regarding the conduct of Pension scheme trustees. This is a potential litigation matter regarding the payment of my late father's pension fund. I require help drafting a complaint for the pensions Ombudsman concerning various matters regarding our family pensions scheme.

Ideally seeking a lawyer who may have expertise in the following; Trustee obligations, Pension Funds, Litigation, fraud.

Prefer someone based in London. Difficult to estimate total time for this project. Can pay hourly rate.