Mapeker is OK for porcelain but the Unibond I don't know. Both of these seem to be rapid set so if you're not an experienced tiler, it doesn't matter how cheap they are, you're going to throw half of it away as it'll be going off too fast for you. I'd still stick with the Adesilex P9.
Yes was worried about the speed. I was thinking is make up smaller batches instead mixing the lot up?
I've bought the Adesilex now in any case. Bought online for 15 quid a bag plus a tenna postage. Just won't be done as quick as the Mrs would like but hey ho!