As far as I can see, the DPS Pandora heatbank has a flow switch to
control the pump and a TMV to regulate the output temporature, whereas
the Gledhill Pulsacoil heatbank doesn't have a TMV. Instead, it has a
temperature sensor on the DHW side and a variable speed pump.

What do people think about using a variable speed pump and temperature
sensor instead of a TMV? Would this approach would also give better
stratification inside the thermal store? How easy is it to find a
variable/multi-speed circulator pump?

Rich.

You'd need a flow switch capable of detecting different flow rates
hooked up to some sort of controller to deliver variable current to
your pump. I guess you could then use a standard pump.

Mike