What's the Name of That Book??? discussion

This was a book or series of books read in the late 80s and early 90s by my 12 year old. The story line involves a brother and sister witch. The sister had powers over nature, and the brother over mechanical items. There was a third character later in the series with power over computers. Possibly published in UK.

Not brother and sister-you're thinking of the Young Wizards series by Diane Duane. The first book is "So You Want To Be A Wizard", where the girl, Nita, meets the boy Kit. In the third book, "High Wizardry" Nita's younger sister Dairine finds a computer downloaded with the Wizard's Manual. (Nita and Kit get their wizardry from books)

Thank you, I'm going to get a copy now and confirm!

Here's the Google Books preview of So You Want to Be a Wizard by Diane Duane - Sue's suggestion:

https://books.google.com/books?id=dfX... There are different cover images.

That's it thank you!!!