I haven't read up thoroughly yet on these particular rule changes, but I didn't think that there was anything that actually specified what the "assessment" had to be, and certainly nothing to say that it had to be an hour in an aircraft.
A lot of these new rules are being left to the discretion of the head of training at each training organisation, so if you find somewhere with some common sense you should still be able to combine everything into one flight (assuming you're competent and don't actually require any training before the test). If you could still combine it all, it would only be an extra 10-15 mins in the aircraft, which would be well worth it to renew the MEP.