Things start getting tricky when you're on a corner plot. I assume that you're No 41 and the front door faces out towards the bottom right on the plan.
BTW is the building near the bottom of the plan another house or is that your garage?
To answer the easy question first:
"Also are we allowed to move our front door to the front?"
Yes, absolutely no problem with that at all.
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"...but as this is going onto the boundary where the pavement is, are there any specific rules regarding how close we can go to our own boundary?"
You can (generally speaking) extend to the side of your property or to the rear without needing planning permission (again, it gets complicated for corner plots).
From what you have said it appears that the main front (the "principle elevation") of the house is the side where you currently have the front door.
If you wish to build an extension in front of this then you will need to apply for planning permission. The planning permission will state how closely to the boundary line you can extend your home.
That is something for you to negotiate with your local planning department.
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In contrast, if you wanted to build an extension on the area that I've outlined in red then you wouldn't need planning permission, but if the building at the bottom of the plan is not your garage but another home then you would need to do a Party Wall Agreement with your neighbour.