first of all 3000£ buys you a lot of saxophone and even a lot of baritone.
As a matter of common sense I wouldn’t buy, even if cheap, a new horn. If you do and you will ever be unhappy down the line you will be hit with a major loss which you never really take if you buy a secondhand sax.
First of all, determine whether you need the low A or not. If you are playing in a big band, you probably do, if you are playing solo in a small ensemble you probably don’t.
This makes looking for a baritone a very different thing.
If you need the low A probably (with very few exceptions) you would be better off with a more contemporary (still secondhand) horn.
Yanagisawa and Yamaha (but even the humbler but better models of Jupiter!) are the usual suspects in the secondhand Low A category within your reach. Mark VI or SA 80 II are not going to be an option, probably, but there is no harm in looking around, asking and flashing your cash.
Don’t be afraid to look at unusual suspects too! I have sold a Grassi with low A to a Dutch member for a very small amount of cash and he is still thanking me! Weltklang? B&S? Dolnet?
If you don’t need the low A (although Martin, Buescher and Keilwerth have had some low A baritones) the choice is big.
Martin, Buescher, King, Conn, Keilwerth, all good stuff!