Chris
The problem here is not the word "services" in the part of the definition of "construction work" that you refer to you but the very last word in that definition - "structure" in itself defined in CDM
“structure” means—
(a) any building, timber, masonry, metal or reinforced concrete structure, railway line or siding, tramway line, dock, harbour, inland navigation, tunnel, shaft, bridge, viaduct, waterworks, reservoir, pipe or pipeline, cable, aqueduct, sewer, sewage works, gasholder, road, airfield, sea defence works, river works, drainage works, earthworks, lagoon, dam, wall, caisson, mast, tower, pylon, underground tank, earth retaining structure or structure designed to preserve or alter any natural feature, and fixed plant;
There was no definition of "structure" in Section 176 of the Factories Act 1961 - instead the definitions of "building operation" and WEC (the latter as extended twice) were framed so as to include just about everything listed in the CDM definition of "structure" but adding, in particular, the last two words in the definition with the stated intent of closing some perceived loopholes.
HSE explained in the Consultation Document for what was at the time given the acroynm CONDAM what they were trying to achieve and specifically referenced plant such as newspaper printing presses - it resonated with me as it was quite soon after the presses in the former Glasgow Herald building had been dismantled leaving the shell of a building around the gap. A huge logistical challenge to do a project whose risks were similar to those of demolishing a building of several storeys.
However this didn't entirely solve the issue as CDM does not contain any definition of "fixed plant"!
Which takes us back to the extensive case law on the interpretation of what was a "building operation".
It's not entirely a coincidence that when I opened up my 1976 edition of Redgrave's Health and Safety in Factories it opened up at Section 176 - that is more often than not where I want it to open!
Redgrave comments quite succinctly:
"No general answer is possible to the question whether the installation of plant constitutes the construction of a bulding. It must depend upon the circumstances of each case whether such an operations attracts the regulations in question or not" - those "regulations" being the four codes of Construction Regulations 1961 and 1966 - most of whose requirements have been consolidated into more recent Regulations usually with only minor changes.
So, since some of the case law said that construction (in the broader sense) of plant was a "building operation" whereas other case law concluded that it wasn't this rather leaves us in limbo - EXCEPT that it really doesn't matter either way since HSWA is there as the overarching legislation to cover any gap in the scope of CDM.