sorry boris, it's a little difficult to follow what yu are saying. you say your uncle left everything to hs wife, but then in the next sentance you say his estate was split between his neices and nephews, which was it?
if your aunt had a will,you will be able to get a copy of it to look at frm the probate registry. If she dies without a will, the estate would have been distributed under the intestacy rules. in order to avoid confusion, as only you know your relationsa nd who they are see here
http://www.hmrc.gov.uk/CTO/customerguide/page1 4-1.htm to see how the estat would have been distributed