I'm mindful of multiple fees from transferring it after every small purchase on the exchange. I know its a risk leaving money on the exchange but I figure risk of loss up to £50 with a reputable exchange like Binance is acceptable to save on transfer fees.
It will all come down to how much you plan on buying and how often, from the start, the withdrawing of £15 is out of the question since that's the fee Binance charges, so if you plan on buying
BTC worth £20 you end up with £5, so I'll say that's just as bad an as a hack.
Raising the sum a bit to see a better picture, if your plan is to buy £100 every week and do so for 3 months then you know for certain two things
- in worst case scenario you lose £600
- you go the safe way but pay each week £15, and you end up with minus £180 for sure.
I guess it would be fine to keep small amounts but why not just use a decentralized P2P exchange like LocalCryptos instead and get your funds directly deposited to your cold storage?
If you look at local crypto for the UK the only nonnewbie guy selling small amounts (under £100) the best offer comes from a guy that sells BTC with a 20% premium. You end up with the same fees in the end.