When you get the test done, get it done by TWO companies and make sure they know you're not using them to remove it, so they have no reason to lie. And make sure they test everything, including walls, loft etc. There are various levels of testing they offer, so go for the top one otherwise it's a waste of time.
I think doing it yourself is stupid, if you can afford to have it removed professionally, but it's up to you. Just make sure you properly cover and seal doorways and skirtings etc. so none of it gets into any cracks, or floorboards etc.