Annoying isn't it, when people don't say how they got on.
Lambda fixed yours, after we plugged in to check its function
Changed the lambda sensor and all 4 of my plugs are covered in black soot now (brand new ones!).
I've given up on it now and having to wait to book it into a local auto electrician.
Were they fitted at the same time as the O2 sensor? If not clean them off with a wire brush and refit.
Is it still misfiring?
From what I've read the CTS, thermostat won't throw up a fault code. Be good to know the outcome to this, there are so many threads on 182 missfire problems at the moment. Shame you can't borrow a known working MAP sensor
Keep me informed on this as I have exact same symptoms, and I've changed my lambda. Mine only rears its head if I pass 5k revs, drive it below that and its runs as normal, apart from 30mpg on motorway run. Not too far from you either at Haydock