Hey. EZO are a good brand they should last a while, as in years, the 6001 2rs you can buy in SKF on ebay for a £3 to £3.50.
I stock all of those bearings you would have paid £5 each for the 6901 2rs with weather proofing and about £3.50 for the 6001 2rs in SKF. Including the postage the cost would have come in at about £15.85.
Still I buy my bearings in bulk and don’t have very high over heads. For the 6901 2rs you’ll be looking at about £7 to £8 where ever you go and £3.50 to £4 for the 6001 2rs in SKF or FAG/INA. £20 isn’t all that bad, I run a long lasting grease in mine, it’s not so thick that it slows down rotation, but it is very water resistant.
Let me know the actual individual prices you’ve paid for the bearings if you can and what kind the 6001 2rs bearing is. That said I would estimate 3 to 4 years use on those bearings, so not bad for £20