I'm considering having a back to wall toilet fitted in my bathroom with the cistern hidden in a vanity unit. I've checked few out and have noticed that the cisterns are very small. Is the flush on these toilets any good? I can't imagine it to be powerful as I think it only holds about a gallon on water.
I just fitted mine yesterday, it has a 6 litre cistern and like yourself I was a little worried that is was going to be too small. However it was tested late last night with out a problem.