For information on the main residence and CGT, take a look at HS283 here
. The fact that you didn't own another property doesn't necessarily make the one you do own your main residence. It could be let for instance.
You say you never lived full time in the property. What does that mean exactly? You are given exemption from CGT for the proportion of any gain you make that is covered by the period that you lived in a property that you considered to be your main home and for the last 18 months of ownership, even if you were not living there during that period.
If the property was not your main home for the entire period of ownership and for a maximum of the last 18 months of ownership, then part of the gain will be taxable and you will need to report it to HMRC in your tax return. Ther first £11,000 of any gains made by an individual in 2014/15 will be tax free.
As your aunt continued to live in the house after gifting it to you, it is a gift with reservation of benefit which means that it remains in her estate for Inheritance Tax purposes until she either passes away or moves out and lives for a further seven years. Given the Inheritance Tax threshold of £325,000 for an individual and up to £650,000 for the surviving spouse of a married couple, this may not be a problem. It was also a disposal for CGT purposes, though if the property was her main home for all the time she owned it, there will be no CGT to pay.
I hope this helps but let me know if you have any further questions.