I have a couple of loo tents. First the grey one - it is excellent for the job,
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It has the advantage of a 1.5m on a side base so there is plenty of room inside, it has a detachable floor (easy for cleaning), space for the porta potti and also storage of of other gubbery. There are nets on the walls for storage of loo paper, deo spray etc. Also opening windows if you wamt to enjoy the view whilst sitting. The disadvantage is that it is a pig to erect threading all those alu poles through miles of nylon tubes - and then trying to fit them into the *crown" at the top.. OK for more than two nights... then the effort was worth it.
Number two tent is as shown in other articles.
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It is quick to erect but has disadvantages. Firstly has no roof - so in wet weather a brolly expanded over the top is needed. Secondly it is only 80 cm on a side so with porta potti inside not much room to shuffle around, close door, lift seat and get positioned. This manoeuvre is compilcated as the structure is very flimsy and nothing to get hold of. Much easier to enter backwards lift seat, get positioned, close doors then drop trousers , etc. A wrinkle is to pitch the tent with door close to a hedge or screen to create privacy, then you can leave the door open. Makes the process much easier if you are not shy,
Hope this helps...