What are these drainage pipes?

Grumpy_chap

Jeepers_Creepers said:

Almost certainly it's as said by others above - from the 2 tanks that used to be in the loft. I'd be reluctant to cut them flush until this is confirmed, tho'. It's possible, for example, that the 2 tanks fed into a single overflow, so that leaves the other as possibly being a toilet overflow.

If you take a spouted jug of water up into t'loft, raise that visible pipe end up and pour into it, that should ID one of them at least. Reward that helpful pipe by cutting it flush, pushing the end back into the soffit and making a nice wee brown cap to go over that hole.

If you really can't find evidence of a second pipe in the loft, then I guess you could try lifting the lid off each toilet cistern on the upstairs floor and activating the inlet valve until it 'overflows' - does any water appear out the other pipe?

THIS ^^
@Jeepers_Creepers suggested.  Alternatively, can you pass a wire down from one end and it comes out the other?  

DPR87

Thanks all. Confession to make....
I went up this morning to have a look...
Followed the single pipe again and I must have lost my bearings last time. That single pipe exits in the eaves to the rear of the house.

So the two above the door must be for the two toilet cisterns (en suite and main bathroom) which are at the front of the house.
At least I know what they are now thanks to all of your input.

Can I still cut them down a little bit so they are less protruding?