Extended skills posts to meet your clinical interests are negotiated between you and your Regional Training Organisation (RTO). Each RTO offers different options.
Once you are with an RTO, talk to them about your interests in advance. This will help your RTO plan out your GP training.
For both colleges, these skills can be undertaken any time after completing core clinical or hospital training. The needs of the community in which a GP registrar intend to practise should be taken into consideration when making the choice.