taper bearing.

[i lunn]

Simply bearings have a major brand (i.e. whatever recognised brand they happen to be able to get their hands on when you order!) 14276B listed for £85 inc vat, with a mjor brand 14125 for £26.
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For something precision, mixing and matching old and new parts is not really recommended.
What's wrong with the original bearings?

The inner race is very notchy it looks to have been run dry.

[fawdry89]

I stock this bearing in my store. It is the un-marked version http://cjfbearings.com/products/1412...roller-bearing

[Ross77]

The races are probably notchy because they have been left stationary with a heavy preload.

The lathe will only be as good as the bearings so it is worth getting good quality ones. I wouldn't think £10 car wheel bearings are not going to give a good result. You can use lower spec bearings but you need decent test gear to find and balance out the high and low spots. You may get lucky but I have only seen cheap bearings used when the the nose register and internal taper have been cut in situ once the bearings have been fitted.

Spindle bearings have the high spots marked and come in matched pairs so minor errors cancel out.

[EddyCurrent]

The races are probably notchy because they have been left stationary with a heavy preload.

Yes, at one place I worked we had a stores with huge electric motors, the armatures had to be rotated 1 and 1/4 turn every 6 months to prevent that very problem.