I live 5 minutes from the lower Thames & used to regularly fish it before a hand injury.
But as a child fished the steps next to Westminster bridge most weekends unless an expedition to one of the following :
Richmond
Hampton Wick
Hampton Court
Walton on Thames
Eton
Windsor
Bray
So I have always fished the River Thames unless the occasional visit to a lake or canal.
So Thameside seems appropriate.