Absolutely true, Heathrow Director.
The reason behind it , helicopter/GA tfc below was also mentioned in the UK CAA publication about this clearance practice.
However it remains a bit odd that this is only in the UK , and not in any other part of the world where I've been cleared for the ILS all the time.
After being cleared to an altitude, mostly the initial approach altitude, than vectored and cleared for the ILS, same for a continues descent which we try anyway and same for the odd ILS without radar , hence following the entire procedure and descending with it on radials and or bearings.
However, it works in the UK , allthough there is a bit more R/T involved , they do not want to change it , allthough they are getting into the "when established on the loc , descent with the glide" phrase in lately as it is confirmed that there is a little to much R/T involved.