Possible Clues:

• Part of Shakespeare play before tea break is put into operation
• Galvanize titanium tank, plugging hole in one
• Increase energy in fourth part of play at Eyemouth
• The fourth part of play swallowed this to get it going
• Launch appeal over tax, expert makes the case
• Cause to start, set in motion
• Cat I, a vet, managed to get going
• Start off with exploit that is to restrict tax
• Cause to move or start
• Just to get one going, had a meal after the fourth part of the play (8)