This video from the 2018 RSGB Convention shows Sam Jewell G4DDK describing his high performance 432 MHz transverter.
Description : G4DDK will be describes a 70cm transverter that can be built from scratch, with the support of a professional PCB, or from a kit. Sam describes the latest upgrades that mean that the receive converter side of the transverter has exceptional strong signal performance together with high sensitivity. The transmit converter side features high spectral purity and the ability to frequency lock the transverter for high stability makes it perfect for both digital and analogue operation.
Note that his website states that this transverter is no longer available. The video was only put up on the RSGB YouTube site on the 6th of June 2019 which is well after when the presentation was made.
G4DDK's website