Changed tyres...hava spare but noticed that there is grease "sweat" in the nice little Alcoa Cap.....does this mean that bearing is going without???? now?
A very thin film of grease on the inside of the cap would not bother me as long as the inside seal and cap were ok. Grease will move by capillary action to adjacent parts.
Your miles are enough that I would want each drum pulled, the back seal checked for leakage, a little grease pushed into the bearings if required and check the tightness of each bearing as it is closed up. Also gives a chance to inspect the brake assembly at the same time and adjust brakes if required.
I do my own. At 12000 miles, you should not need much done. Seals are only 2 years old, grease doesn't escape unless seal is bad. I clean off the needle bearing surface and roll each bearing and inspect for pitting starting on each of the little needle bearings. Outside bearing is easy, inside bearing is a little harder because seal holds it in the hub but, it is still possible to inspect inside bearings without removing. Add a little grease back into the side of the bearings & race and close up.
Only other thing would be if a bearing or brake has been running tight and overheated. Then some further action may be required.