I applied online. The process took 3 months. I interviewed at National Grid (Warwick, West Midlands, England) in Feb 2019
Interview
First of all, there was an online test ( the SJTs and numerical). After that, I was invited for a telephonic interview, where they test you on the core competencies of the company. This was very straight forward. Finally, I was invited to an assessment centre, It had 3 activities: competency based interview, presentation and group task. For the presentation, you get 40 mins to prepare and 10 mins to give the presentation.