Been drinking 60-70 units a week since end of october 2015, is liver damage likely or unlikely? i have no symptoms and cut down to 20 units a week

Likely: If you had a high alcohol intake for months, you are very likely to have some degree of inflammation of the liver (alcoholic hepatitis) that could be measured with a blood test (the level of your transaminase liver enzymes would indicate how severe it is). Prolonged drinking often leads to irreversible liver damage (cirrhosis of the liver), but the amount of alcohol and duration required varies.

Of course!: It's no brainier. It does affect liver, heart and brain. Slow down and seek help before it's too late.