Should I pay off my mortgage or not?

LE3

I have an offset mortgage which was an excellent decision for me & I am now in the position where I could pay it off completely (ie I have more "saved" than "owed") but on the other hand I currently pay £0 interest so could just keep paying off something like £50/month from the capital for a few more years & still have that pot of money available to draw on in case of emergency. 
I am in a job that is considered secure & I currently have around 9-12 months of basic living expenses available on top of what would be needed to pay off the mortgage however I do envisage my 15yr old car needing replacing in the next couple of years (I bought this one used but paid outright, no finance) and really do need to seriously start looking at a new kitchen which I guess will cost somewhere in the region of £8-10K though I haven't actually had quotes etc yet.  
At what point does it make sense to pay off the mortgage which is costing me nothing in interest, and what are the advantages/disadvantages of paying off a mortgage?