We think the lowered height Spax shocks for the front of the Minis  would be correct for lowered Spridgets in the rear:

https://www.spridgetmania.com/part/158-M11GAS/Austin-Mini-Front-Lowered-Suspension-Knob-Adjustable-Spax-Gas-Shock

But, since there's no conversion kit that comes with the lowered shocks, you're in a bit of a pickle. You'd have to buy the standard kit and get the lowered shocks separately. We can't substitute as the kits come to us completely - we don't put them together ourselves. Neither do we offer just a rear kit without the shocks included.

Spridget Mania Tech Team

The Spridget Parts and Accessories Experts

Here's a tube shock conversion kit to fit your Sprite:

https://www.spridgetmania.com/part/SPCK6/Tube-Shock-Kit-Rear-Semi-Elliptic-Spax-Sprite---Mg-Midget

Spridget Mania Tech Team

The Spridget Parts and Accessories Experts