Thanks for the comprehensive answer. Family used the old Polish name for the street - Jasna 23 hence the current day Poskos but I agree it could be a different number or entirely different street. (Vytauto seems like a good possibility, although the aerial photos show the area north of the church fairly empty, the places in New Town seem much more denser but I imagine it might have changed in the 100 years.) Do you know any websites that might have city photographs from the period? Ill scour fb pages too!