As someone working in a Digital and Data role who is professionally registered as CEng, I often get people concerned about relevance of the IET and the Engineering Councils professional registration to those sort of roles.
My answer, is the IET is relevant, inclusive and there are plenty of people from those fields applying and becoming professionally registered. In fact, there is much work on making it more inclusive.
For example, the IET is a founding member of the SFIA Foundation, if you are aware, SFIA as named is a skills framework for the Information age, which covers digital, data and software skills and can be used to prove competence.
I actively encourage people I advise to use SFIA as a guidance to prove competence this way as part of meeting the requirements under UK-Spec. as a rough order, alignment of skill and attribute level is:
ICT/EngTech - SFIA L3
IEng - SFIA L4
CEng - SFIA L5 (as with CITP and CMgr)
There is much more work afoot to make this more incorporated in the processes/ assessment standards etc. but as a start the IET is a great home for those in digital professions and is working hard to make it more so.