It depends of the winds, and of the kind of ship : a merchant ship did not sail much faster than 4-6 knots, whereas a frigate could sustain 12 knots under good weather, and a packet could be even faster - or dramatically slower, if the sea were too rough.

Wellington's expedition took 9 days (12-20 july) from Cork to Corogna; I don't have the exact time from there to Lisbon, because he stopped in Porto and before Vimeiro.

Under normal condition, which are nothern wind along the coast of Portugal, the travel could take 4 days (source : "Histoire du duc de Wellington , Brialmont, 1856" p.72, note 2, on google).

But there is the example of Moore's reinforcement to Wellington in Portugal, which was much slower, delayed by contrary winds (I will check the exact time, I don't have Oman at hand).

Regards,

Jean