What is the complaint? That TT are not providing something that they aren't contracted to supply? The original contract is still being delivered, there is no complaint against the original contract. It is like saying if an altnet turns up then you should be able to get out of your contract with Virgin Media. The contract is not impacted by the fact something else turns up that you would like to go to.
I am not a big TT fan but I don't see how there is a complaint here against the original contract. The ombudsman would I believe just throw this out straight away as TT are delivering the contract.
The case only has to be arguable for reference to the ombudsman. But if you think that this is about winning at the ombudsman stage, then you have completely missed the point.
To go to the ombudsman I think you would need a deadlock letter which I can't see TTB supplying.
AIUI you can go to the ombudsman after 8 weeks. The deadlock letter allows you to go sooner. The hope would actually be to get this to whoever authorises deadlock letters so that they can decide whether it is better to let OP proceed with a complaint [at cost to TT] or for TT to back down.