Hi Rees Perth
First of all, welcome to the Forum.
You say that the westie attacked the hog. By that, do you mean that it actually bit the hog? Or was it just barking at it. If it did bite the hog, you should really have got it checked over because if there was a puncture wound, the hog could get an infection. You can get contact details of your local carers from the BHPS on 01584 890801. I realise it might be a bit difficult for this particular hog, as you may not know which one it is. But you might be able to keep a look out for a sick hog. But dogs can cause fatal injuries to hogs, so if a dog has actually bitten a hog, it really needs checking.
Whether you continue to encourage the hogs, might depend a bit on how much effort you are prepared to go to to protect them. i.e. would you consider only taking the westie out at night on a lead? Or as simbo65 suggests, walk it away from any areas which you know the hogs use.
There is some information here: https://www.hedgehogstreet.org/pets-and-hedgehogs/ You could try some of the things suggested.
Good luck. I hope you are able to reach a compromise which keeps both the hogs and your westie safe.