Having used a number of solicitors and barristers in the world of Employee Relations, Hipennine is right. Ones who know their way through Employment law properly are rare. Ones who know the issues connected with TU and TU disclosure law are even more rare.
There are very few TU disclosure cases.
Further, in much of employment law, many of the individuals and firms that call themselves either "lawyers" or "advocates" are not actually solicitors.
A solicitor has to be 1. Qualified, 2. Admitted and 3. Practising.
The term "lawyer" has no legal meaning in the UK. I'm a lawyer - you are a lawyer.
If I were pursuing Unite, bassa and its "Auditors" I would follow the letter of the law, (as described above) and then pursue the auditors. Use paper letters with proof of posting, collect copies of everything, and then go for the auditors - using The Sun or some other reputable media firm as your helper.