Best way to pay off a few grand?

I need to transfer money to a business. It's almost 5,000eur and I'm trying to figure out the best way to do it.

Transfer Online (AIB Online Banking)
Can I do it with this amount? Would it have a fee?
Once I have the business account details added to my payees. Can I simply transfer that amount like I would do a smaller sum?

Pay via credit card
Phone them and give my credit card details. But I remember reading this might cost 16eur per 1000?

Pay via Cheque (Ulster Bank)
Is a cheque the best option for a sum like this?

Thanks

Online banking would be the easiest way. As far as I know the daily transfer limit is 20k so there would be no issues with a 5k transfer. If the business account is also with AIB the transfer should be instantaneous, if not it should hit the account the next business day

Oh great, easier than I expected! That's the handiest one for me. Thanks for reply