Hi Maisy
I'm 36 and went to two different GP's.
The first GP asked how long I've been twitching, where else I twitched and measured my twitching right leg. The difference in size (1 cm) was, according to this GP, within normal range.
He did a series of blood test, focusing on thyroid + liver function, and CK to see if there was muscle damage. He said twitching was quite common, and wasen't concerned.
A couple of weeks later I moved to Southampton and went for a second opinion. The second GP took one look at the twitching, measured the leg (1 1/2 cm in difference) and refered me to a Neurologist.
The Neurologist stated that everyone has twitching and that the different calf sizes (again 1 1/2 cm) was within normal range.
You should get a referal even if you want to go private. The NHS will make you wait. I've had to wait 2 months the Neurologist consultation, then 2 months for a EMG and now I'll will have to wait 4 months for another neuro consultation to get the results...