Lancashire has quite a few crags that are close to M61 junctions and have short walk-ins. I don’t have the bouldering guide but I’m sure other UKB users can advise on which are best.
I noted how close Nesscliffe is to the A5 the last time I went down to Pembrokeshire, but didn’t find the time to stop, maybe next time.
It's hard to imagine any crag having parking closer to a motorway than Blackstone Edge. Shame about the walk-in.
Similar for Nesscliffe, although it's a bit of a walk to get to the Northumberland wall.
Haresfield Beacon (Gloucester) M5 Junction 12 is a good alternative to Worcester if you want an outdoor alternative. Very pleasant spot with in situ ice cream van.. Alas there are no toilets or coffee.