My question would be: Could anyone recommend a reputable user-friendly exchange which has a sweep feature? I do realise this would mean handing the private key to the exchange, but the amount in this address is not great (even now in these times of peak Bitcoin value!). I just want to sweep it without hassles and complications rather than leaving it there forever. And I guess the exchange would have to be one that deals with these cryptos (BT Cash, Gold, SV, etc...) and not solely Bitcoin. Ideally, I'd probably like to convert these "fork funds" into BTC.
The first is that you are not sweeping, sweeping means transfering a private key from one wallet to another. An example is if you sweep the private key of a paper wallet into an online wallet like coinomi, sweeping will charge transaction fee, that is why it is not the same as private key importation which requires no fee.
In this case, you only want to claim the forked bitcoin cash. Only what you need to do is to get a wallet that support bitcoin cash, not an exchange. Do not give your private key to anyone, it can be used to compromise your wallet and all your coins will be lost. Just get yourself a bitcoin cash wallet that is also noncustodial. Import the private key of the bitcoin address, the bitcoin cash will appear. You can use eletron cash which is open source. After the importation, I will advice you to transfer your bitcoin private key to another safe wallet because of the private key which was imported into another wallet, this is for safety reason.