Septic tank inlet clogged with solidified fat question

[elmocambo]

I'm not sure if this is the correct place to post this question but somebody might know about this sort of thing.
The inlet inspection drain developed a problem in that it wasn't draining efficiently. I had look inside the septic tank inlet T and poked around with a long length of roofing lath and then pulled out a solid white ball of crud. I then filled the bath full of water and allowed that to drain into the system, the water started to fill the inspection drain and the blockage was released. It seems to function correctly now and drains away as it should. My question is how to prevent this occurring again? We are quiet diligent in preventing fat or grease entering the system by wiping utensils before cleaning and nothing detrimental goes down there, muck munchers additive is used every month.
I have had a look inside the septic tank and outlet T and it looks normal as far as i can tell.
It has been inspected and emptied not long ago and deemed to be compliant with general binding rules.
I was wondering if should invest in a grease trap to attach to the sink or maybe a set of drain rods should it happen again?