Any plumber who comes to you in that situation is going to say that as he wants to do the job and be paid by you. He is not going to agree to do the work and start knocking on doors to collect ( or not ) his payment. In any case he is not a lawer and has not perused your title documents.
I would totally disagree with the likelyhood that a blockage in a branch serving just your property is legally properly to be a shared cost. In any case I suspect that you did not take reasonable precautions to prevent it freezing up.
Big Al does not seem to be familiar with the council estates in both London and places like Sheffield where virtually nobody works.
If you need to find a tradesperson to get your job done, please try our local search below,
or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Please select a service and enter a location to continue...
Are you a trade or supplier? You can create your listing free at DIYnot Local