Having never used powdered adhesive before,what is the best way to mix it up?,looking to be using either mapei p9 or keraflex and possibly fibreplan slc,(plastered walls and ply/devimat floor).Thanks.

I use an old sds drill with an sds connector on the paddle. Water then add powder slowley, to much at once could end up with dry addy at the bottom of the bucket

mix it by hand if it's your first time,it'll help you find the right consistancy you prefer before using a mixer,follow the instructions for ratios and start of with some water in the bucket

and when you get your mix right get your,self sorted with a mixer of some description,
Dave at tradetiler has some goods ones lately.

Paddle mixer....mix's the adhesive properly , especially needed when mixing Single part flexi's as you want to mix the hydrated polymers in thoroughly..

a plastering mixing drill and paddle for me

Take your son with you and make sure its 5.5 litres of water to 1 bag of fibreplan.
Got my first paddle mixer 11 years ago when he first started and often wondered why I bothered to keep him!
Now he says the same about me!