Insulated the bottom of the heat bed today with some foil tape. Used 2 layers
Definitely seems to heat up faster.

Also remembered some one saying If you set the temp past where you want it, it will heat up faster.
Yep.
I did time it to 70c the other day. took 12 minutes.
However if I set the target temp at 84c - it hits 70 in 2-3 minutes !
Not sure how much is due to less heat lost and how much just to setting it past the actual temp.
When set to 70c, It basically surged to 65c and then ground to a halt, and crept up very slowly.

Going to experiment to see how much past the actual temp you need to go.