I can see why you would want to sort this out especially if you're having the driveway sorted but to be honest I think you will run into problems if you touch it. There is the issue of the mains power feed running under it and the fact that the existing telephone service may need to be disconnected to get in and out of the new toby box (unless you plan to cut and shut the new toby box around it)

Out of interest where does the existing telephone service first appear within the property? is it the other end of the duct that leads from the cast iron inspection cover?

Yeah, I'm not sure of an easy solution either, not with out disconnecting things. However I did read the Toby box can split in 2 to go around cables so might work if it does.

The duct in the picture goes to the manhole on the service strip, Where you see the cable disappear to the right, it goes into the wall and comes out of the concreate slab in ducting, then goes into the wall terminating into the NTE5. Why it's been done the way it has is anyone's guess.

Half is like mine and other half has capping on outside wall, all built in 91-93

Pic 1

You have the problem of how do you get first toby box off without disconnecting cables.

If you change it OR and the Power Company will have an excuse to claim its your pronlem, and as you said block paving you dont want to disturb the ground and end up with a sunken patch in 5 years just for a cap a can of spray paint could of covered up whilst the driveways up

I'd trust a 30 year old metal box more than a plastic one, especially with block paving supporting it