In reply to Phill_Ferg:
Hi Phill, yes I remember :-)
Two things I see:
(1) virtual class RAL_base_seq_vc extends uvm_reg_sequence #(); is missing the parameter uvm_sequence_item
(2) You are starting another sequence as you are creating: elicia_config.start(tb.APB_mseqr);
I don’t believe your Problem is in the testbench hierarchy.