Vacuum routing is slightly different between certain model years (and US/UK models). Most of this is US-centric information.

There are a pair of solenoids mounted under the intake plenum for fuel pressure and ignition. Lotus refers to these as part #A910E6634F.

I took some time to test and investigate these solenoids (they are identical parts, but serve two different purposes).

These solenoids are a German Pierburg part (#7.12942.00) they are not necessarily an easy part to find (right now, sourcing one is more than $50 USD each).

I tested the solenoid to see the internal routing when energized and when not. The solenoid switches between connecting the top outlet to the bottom-side outlet when energized, or connecting the bottom center outlet to the bottom-side outlet when NOT energized (polarity doesn't matter).

The least expensive replacement unit is an A/C Solenoid Valve part 1470004 or SW9000. This operates in a similar fashion to the stock unit as long as you set up the vacuum lines properly. These can be purchased for about 1/2 the cost of the Pierburg unit.