Speed restrictions are different to altitude restrictions, for obvious reasons, and handled differently. You always have the option to clarify your clearance. Similarly, a STAR is a significantly different situation to a SID and handled differently in every jurisdiction I've flown in.
FAA "climb via" clarification (it's non-UK)
http://www.faa.gov/about/office_org/...nd_via_faq.pdf Question 11 on page 4 may prove enlightening for you? I will seek out some more European based source documentation to clarify the differences further.
You haven't posted the source for the text you quote so I can't double check it, however it makes no mention of altitude restrictions when taking a heading off the SID, which is what you are alluding to. It does talk about being cleared to a higher level and confusion over whether the intermediary altitude restrictions apply, however this is whilst on the SID lateral track. This situation is handled in FAA regulated airspace using "climb via" and in the UK using "climb now", as your friend de facto has correctly stated. The excerpt you've copied does not mention being off the lateral profile of a SID at any time.
It does mention being off the lateral profile of a STAR. These are two very different situations. Read the excerpt you've copied again.
This is not pertinent to the thread's initial purpose. May I suggest debating this in a separate thread, or perusing the source documents.