Joining two pieces of worktop is a straightforward process with the right tools and the right knowhow. Most kitchen fitters will be skilled enough to create a seamless join using a router and worktop jig to cut a curved joint but you can also use a circular saw with a fine tooth blade to square cut the material and create a butt joint. The two pieces of worktop can then be joined using biscuit dowel and worktop connector bolts. We recommend using zip bolt connectors as they have different sizes which can be used on 18, 24 & 30 mm worktops. For jointing 18 & 24mm use the Mini Benchtop connector (6 x 100mm).
This video illustrates the process of routing and joining the worktop https://www.youtube.com/watch?v=6IPtKTx4-rc
When your installer is fitting two pieces of worktop together it is likely there will be a slight gap so they should use ColorFill joint sealant to ensure there is no water ingress and give you a seamless aesthetic.
There are over 250 colours to choose from so it is likely that there is a shade for your choice of worktop.
You can see the colour options here https://colorfill.co.uk/colorfill-search-form/