I guess it's not strictly Potters Bar related but do you want to save £300 on an annual all zones gold card?
I travel in each day to Kings Cross and by tube to zone 2. This years all zones renewal is £2080 (or £1934 with 7% discount). I found out it's possible to buy a cheaper combination of tickets for this journey.
A rail point to point season to Finsbury Park is £896 and a Zone 1/2 ticket is £808. If you manage to retain the charter discount you can get the point to point for £833 though the T&C's say you should only get the discount for the same type of renewal ticket. This totals to £1641 and I now have an Oyster (which won't need reprinting every couple of months) and a printed rail ticket which can stay walletted.
I rarely if at all go outside of zone 1/2 and if the train is suspended for any reason, the tube will accept tickets to Barnet/Cockfosters and the Zone 1/2 is good for the onward bus to here.
Since renewing, WAGN have told me it is permitted to buy a similar combination to Oakleigh Park and then a Z1-4 for £1644. This is valid even if the train doesn't stop at the station on the basis that the zonal ticket is not a season, it's a period travelcard
(sec 17.3 of the NR conditions permits this)
This system works well on all stations between here and Welwyn Garden, with the maximum saving at £475 from Welham Green. Costs for various season tickets can be found on South West Trains
season ticket page which will take a Trainline.com login. I renewed the paper ticket through them no problems as it saved queueing at the ticket office and they posted it to home.
<Zero: Edited only to make the hyperlinks 'clickable'.>