(interestingly there don't seem to be any stations with only one gate, always either zero or two or more).
Even going back to the days of scissor gates and sentry boxes, there were usually two of them.
Hopefully you guys get less fare evasion at your ungated stations than we do here in the mostly ungated London inner-metro services)
Having proactive guards helps, though it varies by operator.
I find TfW’s network a bit odd. All the ‘main’ South Wales Main Line stations between Newport and Swansea are gated except Port Talbot, and in the north they have Colwyn Bay gated but not Holyhead, Bangor, Llandudno Junction, Llandudno or Wrexham.
Colwyn Bay and Rhyl used to be a nightmare. There's a reason that there's anti-climb paint at Colwyn Bay and spikes on top of the wall, when the gateline was installed by Arriva the scallies used to drop their bike over the wall before climbing over themselves, only to find that the staff had ejected the bike back outside. When Rhyl first got barriers there was almost a riot. 175s didn't used to have intermediate door controls so the guards had no hope of getting through a three car between Prestatyn and Rhyl in time to return to the cab.
Rhyl, Colwyn Bay and Chester barriers were installed at the same time by ATW (I think Merseyrail contributed towards the Chester ones) and were supposed to repay the capital in two years. In practice, Colwyn Bay and Rhyl each repaid the capital in three months, Chester took just one month - such was the scale of the evasion.
Wrexham could certainly do with barriers, there's a lot of evasion. The trouble is that not only do you have two entrances, you've also got Central to think about.
Bangor should never have lost its barriers. A now-retired member of staff old enough to remember them (in those days a scissor gate on the footbridge, there was no car park or taxi rank entrance to the platforms) kept records that showed that the revenue recovered exceeded the cost of staffing. That said, the long-distance nature of most journeys from there means that passengers are more likely to encounter a guard.
Llandudno does have a gateline. Not an automatic one, admittedly. Those hadn't been invented when the LMS installed it. It isn't permanently staffed but does get used by RPIs and some guards.
DfT should do this a lot more with franchisees.
Starting with Avanti, please. The high-numbered platforms at Liverpool Lime Street see an absurd amount of avoidance and evasion, there are quite a lot of people at Runcorn who haven't paid in their lives. Preston is likewise far too big a station not to be barriered, and revenue blocks at places like Warrington net considerable sums of money, just as the sum of small, local fares.