Sorry no. You can't use an HMDI cable to connect the Sky Go app to the tv. It will come up on the ipad screen that this is not supported. I have looked online and Sky says there are "licensing issues". I live abroad but still have a live Sky subscription that I pay for and have discovered this issue. The only way round it is to use Sky Go desktop on a laptop and HDMI to tv. Seems stupid to me that can use a laptop and not an iPad but there you are.
Don't forget you will need to set up a VPN to disguise your IP address to a UK one or you won't be able access Sky channels at all. I use a subscription from www.my-expat-network.co.uk. Costs £5 a month.