Condensing boiler no-condensate

I have an Ideal minimider SE50 about 5 years old. After some recent problems I have started taking some notice of how it is behaving and find that it produces very little condensate (about 200 ml per day) even when set low (2 or 3 on the dial). If you listen at the flue about 2 minutes after starting you can hear a gurgling sound which must be condensate within the heat exchanger. If set to high the gurgling is much less which seems to make sense as less water is able to condense at the higher temperatures. My question is: is gurgling normal, and how much condensate should I expect if the boiler is working normally?

I should add that there is no blockage in the heat exchanger or condensate drain - I have had it all apart!

Firstly, these boiler produce littel condesnsate as most is dispached via the flue gasses. In winter you will see them pour out a plume. Modern boilers are more efficient at grabbing the moisture and putting it in the drain pipe. The Keston rarely produces a plume.

The gurgling noise could be scale within the heat exchanger itself, and may require flushing out. Is it connected to a thermal store?

The way the heat exchanger is designed any condensate that is produced inside the heat exchanger runs down an inclined plate under the heat exchanger. This may be blocked but I doubt it. These heat exchangers require a "good" cleaning once a year. Remove the burner and use a plastic tie wrap to poke between the fins especially the bottom fins. make sure all are clear. A bit finicky but must be done. When replacing the burner make sure the large O ring is seated properly otherwise condensate will drip onto the pcb board below. Best order 5 from Ideal, so you always replace it after every service. Make sure the grooved seating of the O ring is cleaned out too. Ring them up.