No problem, I just hope I didn't come over as rude!
FWIW, I too live in a rural area and as I said, have been on my own since my DDs were tiny. I know how it feels to be isolated and vulnerable BUT I have my GSD, who although a complete mummy's boy and coward, doesn't look it. My foster GSD is a wuss too but at least he knows how to bark at strangers!. IMHO all you need is a dog which looks or sounds the part, not even both. One of those is enough ime and imho.
Many's the time I have angrily answered AIBU threads about supposedly dangerous or dangerous looking dogs with the same thing... it's not about the BREED or what that breed can supposedly do! As I said, my GSD is a chicken in disguise, it's my Lab cross, who looks like a full Lab, who would be my comfort if you broke in or threatened me.
But you try telling that to one of my stupid postmen passers by who will scoop their DC up and/or give us a wide berth if soppy GSD and I are passing in the street, but who would happily think that as my other dog is a Lab x he must be an amiable twerp who would go off with anyone for a biscuit.
Wrong!
In all honesty? Go to a rescue (local or national, some independent rescues rehome country-wide) which will vaccinate, chip, assess, homecheck, offer lifetime support and take the dog back in 10 years time if you can't keep him, take your Lab, DH and DC and explain that you have a wuss of a lab and would like a stronger personality but NOT a barker (you don't want environmental health on your case!), who will fit in with your family, accept your Lab and love you all. Let them guide you and go with an open mind. Trust me, I speak of the open mind theory from happy personal experience and as a rescuer. I know, for example, of a certain Jack Russell in rescue who is FAR more of a deterrent to unpleasant types than my huge GSDs!
You mention the occasional vans passing your rural home... this is a bit difficult to me as I have had in rescue some knowledge of certain undesirables which sort of fit that picture but am wary here of accusations of being anti a particular type of people. (Don't care per se but am loathe to say something which might stop others from trusting me if they knew of a dog in need of help tbh).
Do you have any particular problem areas or communities locally?
I ask as there ARE, whether folks like it or not, certain problems in this department, in the experience of rescuers. Mine should be a general rule anyway, sadly, in this day and age - but in particular should this apply to your area - for goodness sakes, NEVER leave any dog unattended, be he in your garden or outside a shop. Even if your garden is what you might consider secure!
All it takes is for someone to pull up in a car, undo a gate or a lead, and your dog is lost, often forever. We see this all too often and I would hate for it to happen because I didn't have the guts to warn dog owners of the risks.