Donnachain,
If you get your hands on a copy of the Planner's Report for the previous application it should detail all the issues and concerns of the planning authority in assessing the previous house application. It should indicate if there were any particular concerns from the roads department or in relation to water and sanitary services etc.. and any planning issues eg. height, access, scale, boundary treatments etc. Also, the conditions attached to the previous grant of permission may specify something that you will need to take into account. The Planner's Report should be available for you to download from the local authority website, but if not, you can get a copy at the public planning counter of the LA. This is public information so it is no problem to request a copy.
However, I would imagine that if your new house design is not hugely different from the previous permission in terms of height, scale, access, materials etc. that the planning authority will look favourably upon the proposal. However, this is only if the planning context of the site has remained the same i.e no new planning policy, objectives or zoning has come into play since the previous permission was granted that may impact on a new proposal on the site. You can always request a pre-planning meeting with the Local Area Planner who should be able to advise you on your new house design or layout and any issues that might arise in submitting a new planning application.