I agree you should get a receipt or at least some sort of acknowledgement.
However, frankly, I never use credit cards to funds poker accounts.
Firstly, the risk of fraud is quite high.
Secondly, some card will refuse gambling transactions.
I use Neteller for these types of thing. It's accepted by all poker sites, I can fund it by payment via bank account (and get it paid back the same way).
I just use Neteller to move money around.
Last time I checked (which is a long time ago, admittedly), Neteller was pretty expensive due to their buy/sell spread on the USD. My account is in USD since almost everything was transacted in USD way back when I opened the a/c.
Even a GBP account has withdrawal charges I think.
As for WH, well they didn't used to be so crap when they had their own poker client. But since they joined ipoker things seem to have gone way downhill. BUT one thing you should check Ian is that you haven't just withdrawn from poker a/c to the betting a/c. If so you still have another layer of withdrawals to make.
Last time I withdrew from WH (just under a year ago) I didn't get a confirmation email. But I got the money 2 days later.