If you loan the business 5k, you're allowed to take that 5k back without needing to pay tax on it I believe. Though it does need recording.
So if you've got a private loan, you've got the cash yourself, you lend it to the business, and then when payments come out of the business to you (for wages etc) you'd discount the figure from that. So you'd only end up paying tax on drawings from whatever the figure is onwards.
I've loaned my Ltd company 10k when I sold the car that was privately owned, for the amarok that is owned by the business. So when I worked the Tax out, I simply discounted 10k first, and then started with the 7-odd thousands tax-free that you'd normally start with, and then go on from there.
Had to show A) the receipt for the porsche (so it's not money laundering or whatever) and show the amount going from personal to business account, and then going from that to VW, and then I took the cash back in stages wage-wise, so noted that each upto the 10k was coming back from the loan.
Speak you your account though as I think I missed out on interest or something similar so diddled myself a little, but not sure.