In the States, however, consonant phonemes and vowel phonemes are differentiated. Sounds like 'WH' and 'PH' are called digraphs, while vowel or vowel/consonant combinations like EW are referred to as dipthongs. Gets a bit confusing!
In other literacy programmes, there is much more emphasis on 'consonant blends' - which is something that the North Lanarkshire programme doesn't really focus on. Some kids pick the blends up easily, while others need more practice. I do think it is helpful to be able to build up word difficulty more slowly for some groups, so I've tried to include words (grouped together) that work on initial and ending blends when kids are learning a given phoneme (digraph/dipthong).
Hope this quick explanation helps, for any visitors to the site from the States.