Sealing a wooden bath panel

I need to cut a wooden bath panel to size and the instructions say that if I cut the panel I'll have to seal the exposed part.

What's the best product to use for this? I have a tin of B&Q wood primer and undercoat - will this suffice?

Responses from some of our very best tradespeople:

"We would always prefer varnish, for ease of use probably an acrylic which could have two coats applied within an hour, rather than waiting for other products to dry between coats."

Charles Burns, Candour Interiors
Candour Interiors is a small company specialising in bespoke fitted furniture and fine finishing that Charles and his colleague formed in 2007, having worked together for many years. Based in a workshop in east London, they have a growing range of truly original and highly acclaimed free standing furniture. They have a team of quality tradesmen for any refurbishment or fit-out work which covers all aspects of finishing; carpentry and joinery to tiling and decorations. At Candour Interiors, maintaining a good relationship with customers is absolutely paramount not only during but after the work has been finished. Charles and his team are often called back to do other jobs and have a great deal of repeat custom.