It is absolutely correct that there are wines which are only available in Portugal and not elsewhere - but exactly which these are is difficult to know because different producers have different relationships with importers in different countries.
But I would also offer a counter-argument to the earlier ones on whether port is cheaper in Portugal than elsewhere. In my experience, it depends greatly.
If you visit some of the shops in Oporto you have seen mentioned here from time to time (such as, but not only, Vinologia) you will have a great opportunity to taste and buy ports from small or independant producers that you will not see very often outside Portugal. The prices are cheap / fair and the product you are getting is made only in very small volumes. On the other hand, if you go to the lodges with the big names, you will see prices which are designed to maintain stock levels and remunerate the shippers properly for any sales which they make from their ex-cellars stock - most of the big shippers do not want to sell out large volumes of the small numbers of bottles that they have left in the cellars in Vila Nova de Gaia and price their wines on offer accordingly.
Another opportunity is if you visit the vineyards. Again, the independant producers are often very happy to sell their wines to you at the cellar door for the same or a similar price to their trade price. I won't name any because I would not want to risk damaging any producer / buyer relationships, but you can always call ahead and enquire whether a producer will sell direct and what their ex-cellar price would be.
Let us know if you want some help in finding port shops in the UK when you visit. More importantly, tell us when you plan to visit and we will organise an off-line to honour your trip to the UK
Top Ports in 2023: Taylor 1896 Colheita, b. 2021. A perfect Port.
2024: Niepoort 1900 Colheita, b.1971. A near perfect Port.
Port wine should perhaps be added -- A Trollope
