£20k to set aside for a year - suggestions?

Welcome, cooper_cja, and good luck with your student years.

"I am a tax payer at 20% with no debts and no financial sense!"

Disagree with the latter, because the former indicates you've already surfed around this site &/or read Martin Lewis's book! :-)

Savings Fountain contender Derbyshire Bdg Soc may be a safe place for you to start, because in the event of urgency you could make one withdrawal from that, any time in the year whilst filtering in up to £12,000. It currently offers 5.85% gross interest, & the Society has a reliable track record with rates.

If you feel inclined to gradually tie up a total of £6,000 (or less) in an Abbey Fixed Rate Monthly Saver a/c @ 6.50% gross, you may wish to rush to a branch, this Thursday. Being the final day of a month, you'd be just in time to invest £500 immediately (if in cash, it will earn interest same-day!) Then immediately you have Standing Order (or Internal Standing Order) arrangement made, you can get your October deposit added in.

Halifax Regular Saver also has stringent withdrawal restrictions, but @ 6% gross, it could handsomely reward a total of £3,000. If you have, or open, a Web Saver a/c with Halifax (@ 4.90%), it can be set up to make monthly Internal Standing Orders direct to Regular Saver. So you could feed £250 into Web Saver any time each month, ready for the transfer into RS a/c, without having to remember a specific date for Standing Order payment from an external bank.

During the interim period your funds could be in the best instant access online savings a/c. Tomorrow is the final day for opening a Birmingham Midshires a/c @ 5.40%. After that, the new version of the a/c will pay only 5.10%. Frankly, potential a/c holders may just as well opt instead for Norwich & Peterborough BS whose NetmasterGold Saver a/c pays 5.10%. It offers instant transfers to their cheque a/c, whereas Birmingham Midshires take up to 4 banking days to transfer funds to/from the linked external bank a/c. Alternatively, Abbey's eSaver would be good for the 1st 6 months while the bonus rate makes it 5.10% for £+. Outward Standing Orders (eg to the Derbyshire a/c) take 1 less banking day via Abbey a/c, compared with N&P's cheque a/c.

Or, as djohn2002uk has mentioned in another thread, a lump sum could be placed in a Bond. Northern Rock have one @ 5.50%.