Because of the odd rear offset (any kind of a negative offset is an oddity, there are no widely available wheels that will fit a negative offset,) there are a couple of options:
There are manufactures who make 2 or 3 piece modular wheels. These wheels can be made to a variety of widths and offsets. Be aware that you are very limited to the styles of the modular wheels, and they are usually expensive ($500+US per wheel.) Some of the more popular modular wheel manufacturers:
A second option is to fit newer 5 bolt BMW wheels to your Lotus. You have a lot more options when it comes to wheel selection (and much better looking wheels.) There are pitfalls using this method as well.
The first issue mounting BMW wheels to your Lotus is adjusting for the offset. Most BMW wheels are fine for the front (with a positive offset,) but you will need to fit a spacer to make up the difference for the rear. H&R makes a 40mm spacer that will make up the difference. The problem is that the spacer is made to fit on a car with wheel studs. The Esprit uses bolts instead of studs. JAE usually carries the 40mm spacer.
The second issue is making sure the center bore matches the Esprit. Most after market wheels have large center bores with a hub centric ring that step the bore down to whatever vehicle you are mounting the wheels on. Most BMWs? require a center bore of 72.56mm and some require a 74.1mm center bore, so the wheels will probably have a center bore of 74.1 or larger. You can purchase hub centric rings that will reduce the center bore from 74.1 to 70.5 and then machine out the ring to 71mm.