These SOW reviews seem to take unreasonable amount of time from many casinos (like we can see from threads here), if you do get reply you are afraid (which you really shouldn't as money you use is legit and source of it can be seen) and casino don't want to change their mind, i would use PAB service from Casinomeister, here is link you can see how it works (it's completely free and maxd and team take your case review it and try to sort it out with casino to get fair outcome):
PAB
But i honestly believe that they do pay your winnings. Don't know this group at all but good thing is that they do have UKGC license instead of Curacao so they shouldn't be do that dirty tricks. Give them some time (even it takes long, lately we have seen loads of these which been taking for weeks) and if you really don't get anywhere, use PAB service (read rules, most important is that while complaint is in progress, you are not allowed to make any further posts about case which makes Max and team work really annoying and your PAB in danger if you don't let them to do their work). But like said, wait until you get an answer. If you think to self-exclude yourself, you could do it already now or at least you could set yourself £1 loss limit that you can't by any chance lose your money back (many casinos tempt to reverse your withdrawal back to your account even reversing withdrawals is not allowed on players request but if it's pending there very long, some do add it back to your balance).
You really shouldn't have issue due to reason that you have taken personal loans, as long you they can see from your statements that you have had legit source of funds you have played, they have no grounds to confiscate winnings (which they should then report to authorities if they suspect any criminal activities).
So simply, if you can show that you have legit funds to fund amount you have deposited, all should be ok. If you have deposit more than your legit incomes cover, you might be asked more and more proofs where these funds are from, but really hope it's just one of these cases where casino is extreme slow which unfortunately been seen a lot. Make sure you don't play your winnings back under any circumstances and if there are any unreasonable BS that they don't want to pay your winnings only because you have used loaned money, use complaint routes (PAB is free and top notch quality), for now you only can wait that they reply to you, you can contact support there and then just to remind that you exist.