Wikipedia? 

https://en.wikipedia.org/wiki/Catalogue_of_paintings_in_the_National_Gallery%2C_London?wprov=sfla1

A level history of art text?

Thanks Pinkus - I did try Wikipedia, and the NG website. I'm looking for a deeper dive, maybe indeed education is the way forward (thinking of evening course in Appreciation of Art, but want to study what I like, not what they decide on)

which period / type of works are you looking at? for Sebastiano (never Piombo, btw), the leading text is Michael Hirst's book. Hit me up on anything else. 

Hire a tour guide?

Maybe have a look at Smarthistory. It's an good site for people interested in art. 

If you're interested in learning, get a book or podcast/audiobook on art history. If you like particular eras or artists then get books or other materials on that. A book that has a historical timeline overview would likely be very useful for you (from early renaissance onward). Then you can focus on things you like. 

The national gallery has excellent examples from pretty much every historical era. 

Before the age of 24 (back in 2006) I'd never been to an art gallery and definitely didn't want to go to one. Boring.  I randomly went to an impressionist exhibition (as then girlfriend wanted to go). It blew me away - I couldn't believe that people painting could produce such vivid feelings. So I started going to every gallery, every exhibition and reading loads and loads about it. Your tastes change, too. 

Thanks Escaped - as you see, I do need educating! Maybe SJH is right - I'd really love a tour where I chose 3-4 works(eg Joseph Wrights' experiment on a Bird) . Wish Sister Wendy was still with us, there was always something peculiar about a nun describing the texture of a woman's pubic hair.

I am sure there are either professional curators who offer this, or else keen recent arts graduates. As you say, bespoke the tour.

Best art gallery for me is the Frick, but the Rijksmuseum is great, and has a wonderful app

I think, somewhat understandably over the last 12 months, that I've been increasingly drawn towards majestic inspiration - either in art (paintings) or via classical music (Purcell, Handel, etc). My younger self would be sneering at such pretensions, but I guess I'm maturing, at long last. Thanks all for your guidance here 

Best art gallery for me is the Frick

I love in the Frick those Holbein portraits of Thomas Moore and Thomas Cromwell either side of a fire place, staring at each other. 

Fave is Kunsthistoriches in Vienna. Could spend way too much of my life in the. 

Do you like the portraits collection in the NG? there's a lovely book by Lorne Campbell who is the don of the Arnolfini double portrait.

If Sebastiano is your bag (mannerism - which good ol' gombrich is quite sneery over) - the Linda Murray High Rennaissance & Mannerism book was the A level text of choice and then John Shearman, but that has terrible (no) illustrations. For a slightly earlier skew, Michael Baxendall will lead you up the renaissance. All these are v established / 1970s texts and none the worse for it; no bollox about feminist interpretations of Raphael's madonnas etc.

(have a look at some pictures by Andrea del Sarto and Pontormo and report back, pls. I would like to hear your thoughts. ALso mannerist architecture and sculpture is The Tits. Check out Palazzo del Te and weep)

+1 for Gombrich book. 

The Courtauld used to run free curator tours at lunch. Maybe other galleries do the same. Most also run courses in various subjects - V&A is particularly good for this. 

UAL runs short courses in history of art. I did one that ran on Saturdays for a month. The morning spent walking round London getting a guided talk on history and architecture of the period under review. Then the afternoon in a gallery getting told about paintings of the period. 

Forget Gombrich.  Try Honour and Fleming.

I miss Brian Sewell ❤️