You may get a few blooms here and there throughout the summer, but you will miss out on the big show which is the first flush. Mine is already sending up buds, though still green and deep inside. I wouldn't touch it now. Wait until the first flush begins to fade.

Which variety of Veronica?

Mine is Royal Candles.

I was wondering which one too. some of mine never repeat others never seem to stop.

You can give it a light 'haircut' when the initial blooms fade, but not down to the ground. Then give it a good feed. It will or should send up secondary blooms, but not as spectacular, but nice anyway.

Thankyou everyone for your very helpful answers.