booking another flight

can anybody advise and hope can make sense of my ramblings, have flights booked with online company [not direct]
and got great price but now worrying about the transfer times - going dublin-gatwick-orlando the flights all booked on the one ticket so should be ok, but wondering if i was to book flights with aer lingus the night before and stay in Gatwick and not use the aer lingus flights from the next morning would this invalidate the second leg of my journey? I normally do belfast -mco via newark but its continental all the way so normally no probs!

If I understand your somewhat convoluted description correctly, you have a single through ticket DUB-LGW-MCO. With a single ticket covering the entire journey, if you do not show up for any leg, the remainder of the ticket will automatically be canceled. So, yes, as you suspected - if you do not use the Gatwick flight, you will lose your Orlando flight as well.

If the transfer time is short, your Gatwick flight is delayed and you miss your onward connection, you will lose time but no money. Since you have a through ticket, it is not your problem to book a different flight. The airline will do it for you.

Undo, thank you for the information.