I am quite new to varnish however I have configured varnish in my Dev environment and seems to be going well.

The cache however doesn't seem to flush with Magento. Subsequent requests however remain lightening quick with the old content until refreshing the page on a client PC which them seems to reload the page properly and update the cached page. 

I have run the below command to update the cache host:

    bin/magento setup:config:set --http-cache-hosts=localhost:80

I was unsure about the port whether 6082 or 80 but checking for purge requests with below command shows results when running a cache refresh:

    varnishlog -g request -q 'ReqMethod eq "PURGE"

Result: 

	*   << Request  >> 98314
	-   Begin          req 98313 rxreq
	-   Timestamp      Start: 1511438530.550488 0.000000 0.000000
	-   Timestamp      Req: 1511438530.550488 0.000000 0.000000
	-   ReqStart       ::1 41502
	-   ReqMethod      PURGE
	-   ReqURL         /
	-   ReqProtocol    HTTP/1.1
	-   ReqHeader      X-Magento-Tags-Pattern: .*
	-   ReqHeader      Host: localhost
	-   ReqHeader      X-Forwarded-For: ::1
	-   VCL_call       RECV
	-   VCL_acl        MATCH purge "localhost"
	-   VCL_return     synth
	-   VCL_call       HASH
	-   VCL_return     lookup
	-   Timestamp      Process: 1511438530.550571 0.000083 0.000083
	-   RespHeader     Date: Thu, 23 Nov 2017 12:02:10 GMT
	-   RespHeader     Server: Varnish
	-   RespHeader     X-Varnish: 98314
	-   RespProtocol   HTTP/1.1
	-   RespStatus     200
	-   RespReason     OK
	-   RespReason     Purged
	-   VCL_call       SYNTH
	-   RespHeader     Content-Type: text/html; charset=utf-8
	-   RespHeader     Retry-After: 5
	-   VCL_return     deliver
	-   RespHeader     Content-Length: 226
	-   Storage        malloc Transient
	-   RespHeader     Accept-Ranges: bytes
	-   Debug          "RES_MODE 2"
	-   RespHeader     Connection: keep-alive
	-   Timestamp      Resp: 1511438530.550634 0.000145 0.000062
	-   ReqAcct        65 0 65 218 226 444
	-   End

Why do i still need to refresh the page on my client PC in order for the content to update?