How do ERCs work?

Hi all - looking for some advice on how ERCs/remortgage would work.

Currently with Nationwide - 5 years left on a 6.79% fixed mortgage (taken out in 2007), 184k left against a property worth (a pessimistic) 225k.

Looks like we may be coming in to some money and, having looked at all other options, paying off a lump of the mortgage and remortgaging to a lower rate is the most sensible for us.

Now we will have 60k to knock off the mortgage, and there is a 6k ERC on our deal.

So how does it work it practice?

Do we pay 60K into our nationwide mortgage and this will leave us with £130k balance (184-60+6) which we can then remortage away at our leisure?

Or would that trigger 2 ERCs? i.e. 1 when we pay the lump sum in and a second when we settle the account and remortgage away?

Thanks,

Tim