I suspect this isn't possible but, asking on the off chance that I have missed something...
When adding a handler to invoke a data source method on a stored procedure, Radzen generates the server as a HttpGet. Is it possible to specify that these should be generated as HttpPost with the parameters passed FromBody instead?
There are two ways for executions of a stored procedure:
The procedure that will return data:
General stored procedure execution:
More info about how Radzen will decide which approach will be used to execute the procedure can be found here:
In both cases HttpGet will be used. If you need HttpPost you can create custom method and use one of the two approaches to execute stored procedure.
That's perfect. Thanks for the information and I've now got a working custom method solution 
