Maximum length of BT service characteristic value

I'm trying to put more than 22 characters into a bluetooth service characteristic value. I can see from targets/esp32/BLE/esp32_gatts_func.h that the maximum value is defined as 22 however this value is never referred to again in code (at least I can't see where it is). When I try to fit a string of more than 22 characters it repeats 22 characters of the longer value.

Anyone had any luck presenting a value longer than 22 characters?

I'm using the Device Name org.bluetooth.characteristic.gap.device_name 0x2A00 characteristic with code something like:

-- snip

0x2A00 : {	
	value: "123456789abcdefghijklmnopqrstuvwxyz",
	maxLen : 127,  //this has no effect
	readable : true, 
	description: "123456789abcdefghijklmnopqrstuvwxyz"
}

-- snip

p.s. Loving Espruino, it's fantastic. Keep up the excellent work.