Makes no difference- there aren't any concerns with running HDMI and aerial wires together - unless of course you're using crappy aerial wires and 'HDMI' cables that don't meet the HDMI specifications.
I've seen hundreds working perfectly OK, and fitted loads as well.
I suspect it's yet another of these 'urban myths' which seen to appear from nowhere?.
Nigel : I am surprised at you saying urban myth , we are trying to offer advice to the OP . The issue crops up quite often and of course well screened leads will minimise the problem but unless we mention it to the OP who may not have your skills he may have a unexplained loss of RF signals on freeview stations -- but by then his cables will be well and truly buried in the wall !