It’s a toss up between the cheaper one (VUSA) and the one that includes Canada (VNRT). Not a lot in it, just depends whether you mind paying a little more for exposure to Canada really.
I can’t quite see from the screenshot whether you hold VEUR or VERX; the latter would be better if you want to hold separate UK funds, like VUKE and/or VMID, as it avoids duplication.
If memory serves, VERX does have a slightly higher spread though as does VMID, so, again may be down to if you’re willing to pay a little extra. Much of a muchness really.
If you mainly hold UK stocks, you may want to go simply with VERX, especially if you hold a wide sample of Ftse 100/250 firms – otherwise, you may be more exposed to the UK than you intend.
Another thing worth noting: you may not want to hold only Vanguard funds. Although I’ve never really seen much of a problem with it, others do.
If you do decide to swap some out for alternatives, such as from the likes of iShares etc, it is worth noting that the underlying indicies are often different.
Vanguard tends to track Ftse indicies whereas most others track the MSCI equivalents and the components of those indicies sometimes differ.
For example: I can never remember which way round it is, but mixing and matching Vanguard and iShares funds for the pacific and emerging markets can/could preclude or double up on Korea.