Britain had little reason to trade Portugal for German goodwill

Did pre-First World War Anglo-German discussions mean Britain wanted to partition the Portuguese Empire?

No; the proposals were largely German-led and outweighed by Portugal's value as a long-standing British ally.

Anglo-German discussions do not show that Britain wanted Portugal to surrender its empire. The partition initiatives were German-led, and Britain mostly ignored or humored them. The Anglo-Portuguese relationship offered London a useful and dependable partner that was more valuable than accommodation with Germany. British tolerance of Portuguese rule in India after Britain itself left the subcontinent reinforces the point that London had no automatic interest in dismantling every allied empire. The watch point distinguishes diplomatic conversation from an adopted British objective.