Tips on pre-ordering tickets to Bond premiere in England?

I'm planning to travel to London to see Bond 25 in April when it releases. I've never been to England (from the US) and think this would be a really cool way to see the new film. What's the best way to pre-order tickets to movies there, and how far in advance can one typically buy tickets like this?

I know this is still super early - just trying to gather some initial info to formulate a plan for everything.

Thanks in advance for anyone with more insight! Suggestions of a particular theater in London would be welcome as well. Maybe there are special events for these? Did anyone go to a previous opening night event for Spectre etc?