We need to be very wary of tarring all travel agents with the same brush. Travel Agent is actually a very unfortunate job title, as in the public mind it confers presumption of the same competence and professionalism upon any holder of one of a diverse range of posts. In reality, you may be served by a highly-knowledgable experienced professional who will save you both money and hassle by applying their genuine travel-expertise. Or you could be connected by phone to a halfwit who will by default stick all UK-originating passengers on BA from LHR and apply the preceding Shuttle connection from the nearest available regional airport. Unfortunately, many of this sort are so extraordinarily clueless that they will routinely book some minimum connecting-time horror at LHR taking no account of the limitations of elderly or infirm clients. This is a particular problem with some of those booking on behalf of cruise lines. I know several people who have missed LHR-MIA flights because of this including a blind lady and her elderly helper who were booked on a minimum connecting time Shuttle from MAN. The stupidity is staggering, and those call-centre types in Southampton and London don't learn. Or aren't trained.
I actually told one such 'travel agent' that a connection of this sort wouldn't work and insisted on the booking being made on the previous Shuttle. He began to argue with me and claimed that the connection was "no problem". I should trust his professional reassurances. So I asked this (East European) gentleman how many years he'd worked at LHR or MAN to know this. He hadn't worked at either, of course. I asked him how many times he'd made this connection himself. Never, of course. Then I informed him that I'd worked at and flown via BOTH airports over many years and told him to get the booking done according to my instructions. He was super-snotty about it.
Meanwhile, my cousin told me that they always book with the same "simply wonderful" travel agent. They live in Greater Manchester. But they'd been booked on Thomson from LBA to PMI. How had that happened, I enquired? Well, the MAN flight was full. So what about the Jet2, the Monarch, the Ryanair, the EasyJet - were they all full as well? "Oh do they fly to Mallorca as well? She just told us we had to fly from Leeds. Such a lovely girl. Wonderful." And by the way, this has happened to them TWICE! I told them I would do their future bookings for them if they wanted, and explained to them that they were dealing with a "holiday shop" dedicated to selling the programme of one company only.
Conversely, there are some truly outstanding travel agents out there. The trouble is that they hold the same job title as these morons. You really need to be aware of which sort of travel agent you are dealing with.