Either due to the girl being older than she had appeared, or perhaps some wayward effect of being a forty odd year old woman trapped within the confines of a teenagers husk, the Trace was made inactive. She could practice using this body and enhancing it as much as she wanted with no worry or hint of fear, no one at all within the Ministry able to know she was doing anything at all. Within the first week of arriving at the Muggle’s residence, Bellatrix took the freedom of their absence for an afternoon trip to Diagon. A quick  Apparition,  some time spent wandering (during which no one at all looked out of sorts at her, no one hassled her or called for Aurors to detain her, Merline it was a bloody fucking miracle), and then it was off to Knockturn in search of all sorts of ritual ingredients.