Electric Bike Conversion Kit

To all the experts out there, I recently purchased the discounted Calibre Point bike and looking to convert this to a pedal assist e-bike. Have no clue what's best! Will mostly be used on urban terrain with some off-road use. Mainly looking for distance and ability to easily do inclines. Not looking to spend more than £300 or so (if that's possible). Hope someone can advise. Thank you all!