It really doesn't relate to tesla at all.. it's level 3 autonomy up to 40mph on motorways (or I guess suitably partitioned A roads). Whereas previously we'd have just waved the EU regs into law we have to implement it ourselves now, hence this consultation. I don't see the government varying from the text of WP29 any time soon, though.. we're frequently the ones pushing for more restrictions in UNECE.
Useful for companies wanting to test level 3 tech as it gives them a legal framework with which to do so... but not really practical for a full rollout - that will require further time.