If you don't see any value in using a FA/Planner, don't use one.
My guess would be that you'll be put through to a tied agent in Irish Life and it'll be the same as buying through a FA/Planner, cost wise.
If Standard aren't doing Child Savings/Trust plans directly/execution only then it's unlikely that they'll do a Section 73 policy. I don't know. They keep telling the broker market that they're only doing this type of business on an incidental basis but I've no idea how true that is. I'd be confident that they'd play it down for the brokers ears anyway.
If you 'kind of' have an idea what you're looking for, use an advisory service.
If you know (and understand) exactly what you're looking for, contact an execution only intermediary stating the product, provider and fund/s you're interested in and that it's in respect of Section 73. They can then give you a cost.
Sample technical document attached from one of the providers.