Assuming you mean Veronica gentianoides 'Tissington White', then it is possible to split the clumps, but do it in the autumn, when the weather is cooler and damper.

thanks for answering my first ever post Bamboo.Aalthough I have spent 10yrs building my garden from a derelict plot I have such a lot to learn.From the hundreds planted I am now learning which plants I like,want to keep and those that "dont fit"so to speak.
sheila

It's a big learning curve, but so interesting - and even when you think you've got it right and you're finished, you won't be - new plants come out and we always want them, lol! Enjoy