I emailed the Muslim Council of Britain, which is a national representative Muslim umbrella body with over 500 affiliated national, regional and local organisations, mosques, charities and schools, to provide some guidance on this issue. Their reply was:-
Thank you for visiting our website and contacting us for the said issue. Islam values and respects different faiths as well as customs of various civilisations. It is important to know the difference between bowing and prostration. There are different schools of thoughts in such matters but a large number of Islamic scholars wouldnft consider bowing in front of a person during a specific situation similar to prostration to Allah (swt).
Our acts as well as intentions are known to Almighty and you may ask the gentleman to contact me to discuss and clarify it further.
As in most things, it depends upon who you ask. See this example of Islamic reasoning for prohibitions against bowing, even for a simple greeting:
Of course, there are Islamic opinions to the contrary floating around the net as well.