Lowest guy on the seniority who flies a jet as an FO joined the company 4 years ago. They took a basing in the frozen north to get this. Lowest person in a base like SOU joined the company over 5 years ago, for BHX it's just under 5 years.
That and the fact that most e-jets are mainly replacements for Q400's, most movement will be done in base from Q400 -> Jets, and done on seniority. Expect a long wait...