building chords one finger at a time as you change chords will go on a while.

Muscle memory.

Alongside practicing your changes also practice making and holding the chord shape.

Make the chord, lift your fingers a short way off the chord then replace with normal pressure.

Lift off and repeat.

This puts the shape in to muscle memory rather than the making of the shape finger by finger.

Start using a metronome,changing your chords using beats 2,3 and 4 . If you aren't in place for the 1 beat then your speed is set too fast. This gives you something to measure against as you are able to increase the speed of the metronome. Because it's natut=ral to get frustrated thinking your not making progress but you will be, it just will be slow

6 months on and I can make and change chords but not at a speed able to play songs yet

Dave