Advice on reducing CGT liability

[JOHNRE]

Hello there....
In April 2014 we purchased an apartment in Manchester. Our intention was to retire there in a couple of years. In the meantime we would rent it out, so we put the apartment in my wife's name. She is a non-taxpayer and I am close to the 40% bracket. We have another property which is our PPR.

What actually happened was that our son returned from Brazil and, for the past two years. he has lived there as his main residence (rent-free!)

During the next few years he is likely to spend a year abroad and then about a year back at the apartment, and so on. At some point down the line, we will want to sell the apartment and are looking for ways to reduce this liability. Some questions....

1. Potentially,we may be interested in gifting him a share of the apartment so that, officially, the apartment would be his PPR and, presumably, when we sell, that would minimise the CGT payable on his share? How would this work in practice?

2. If my wife gifted him a 50% share of the property straight away, am I right in thinking that the CGT liability on the gift would be on the increase in value of the 50% share she is gifting (rather than the total increase in value of the asset)? The flat has gone up around £20K since purchase. My understanding is that this £10K would be within her annual CGT allowance of £11,000? (although I have also read that because the value of the gift is greater than £44K she would have to declare it on a tax return).

3. If she gifted him the whole value of the flat (say 50% now and 50% in a couple of years time) would there be any CGT liability when he sells (assuming that she lives more than 7 years?)

Any advice on minimising tax liability in the future would be greatly appreciated!

Thank you

John