Radiator Flush (no drain tap)

I am preparing to by hyper efficient and drain/flush and replace coolant in my Series 3 petrol. I did it last year but cant remember how as there is no drain tap in the bottom of the rad..? I think what I did was take the plug out of the engine block and then just stick the bottom hose on loosely and run the engine. Can anyone give me some pointers as what to do in the absence of a tap? Thanks

take the rad off run the water in the bottom hose point and let it drain out the top hose point?

take the bottom hose off like every body else?

Leave the rad in and turn the car over.

FFS are you ****ed? The radiator was has drain plug .

Why do you need to flush it if you did it last year? I doubt if you have done thousands of miles. If you flushed it properly last year it won't need doing for another 4 years.

Col