Scratch coat.

I think you need to get a plasterer out to look at job or call a local plasterer for advice

Have you put to much lime in your mix,have you used sbr which is also mixed in with your render mix

Pva the wall first use soft wash sand and cement no lime because lime is only used to stop the sand and cement from going off so quick its a retardent has to be nice fluffy mix aswell

Lime becomes a very sticky substance once mixed. If its in the plans to use lime i would use lime dumpy bags that is premixed. Pre wet the walls down, Scratch coat with haired lime and top coat with unhaired pre mixed lime. You will also find that the bricks are to smooth for anything to stick to, even with sand and cement. So prior to scratch coat i would apply a scat coat pver to give it something to key to on your first coat.

You need to ad opc to the mix 4 parts plastering sand 1 part opc that will be fine

What lime mix you using ?? As I a traditional plaster and modern the texture and material account for a lot how long before you applied the scratch coat did you wet the wall ???
All materials need a small amount off suction to add strength and drying ability