Its a long shot, as its probably a house coded part.

Its a Crivit Sport LED bicycle lamp from the Lidl discount store.

Originally it was the LED that went intermittent, but when a second unit
died I decided I could spare one to experiment on.

Suitable LED parts are on order from Ebay, but I thought I'd have a go at
upgrading it with a switch mode current control. The circuit is ready, but I
need to identify the "glue logic" type stuff on the PCB.

The on/off button is a simple pushbutton, the latching is done
electronically. It also has a low battery warning LED - these features would
be nice to retain, but I need a little help identifying the stuff on the
board.

Thanks.