Whether the circuit board inside has a simple switch to select 32A, I don't know, worth you taking cover off when disconnected, & having a look. Also have a look at the big, chunky black boxes which are the relays used to act as the Contactors. Note any part numbers & post them here, we can check the rating. I'd expect them to be 30A rated, maybe 40A, but if they're only 20A they won't cope with 30A draw, so they & probably the PCB can't be upgraded.
Assuming that bit's ok, you'll need to change the cable from there to car for a 32A one. Opinion seems to be the easiest ?cheapest? way is buy from e.g. evbitz.uk, and flog the old one on eBay.
You'll need your sparky to check the wiring from CU through to EVSE is heavy enough gauge, and uprate the RCD/RCBOs. Don't go for 32A RCD/RCBO items, that's too close to the limit, an EV that draws true 32A will trip them in about 10 minutes use! Go for 40A rated.
If the PCB can't be upgraded, I personally would take it out, and flog on eBay for spares to repair someone else's broken EVSE. We had one such person here about 6 months ago, builder wiggled cables, knocked chips off the PCB & blew it up.
That person was quoted about £450 for OEM repair! Instead he posted it to evbitz who mended it far more cheaply by replacing PCB with entry-level Viridian ECU, cost about £80 for that item.
So you could go the same way.
If Car gets charged OUTSIDE the gge, you now need either an Earth Rod somewhere, or what's called PEN-Loss detection gadget fitted, may be called PME Failure, or similar. Newest Viridian ECU has this feature, cost about £125. £185 if you go for optional-extra DC 6mA leakage detection gizmo, your call.
Then, because you removed the PCB with the Contactors on, you need a 32A 2 Pole NO 240V coil Contactor, good quality.
This will take the L & N wires.
If car ALWAYS charged inside gge, Earthing is from house Earth, job done. If you have Earth rod, E wire to car gets connected to that, job done. Else, you're charging outside the house/gge, and no Earth rod around, you must have the PEN-loss device, and this requires another Contactor. Again should be 32A or more, but only 1 pole is needed. You can use a 2-pole one, as much more common, and ignore the unused pole.
Somewhere along the line (in a mini-CU maybe) you'll need a breaker switch, and an RCBO.
If you get a special RCBO with a Type A curve, this has the DC 6 mA protection, so the Viridian won't need he £60 extra DC optional gadget, so a useful saving. But this is a rare, expensive and hard-to-find item. You must double-check the specs, make sure it has the DC as well as standard AC protection stuff.
It's a bit tricky finding some of these items, and here have been some very cheap, nasty & dangerous RCBOs used in EVSEs, so I personally would not under any circumstances go for the cheap ones. Your life/house isn't worth risking it. Garo have a good reputation. No doubt other mfrs are good, but how to tell? There's an awful lot of this kit on sale all over the place. Would be good for some sparkies here t tell us who are the good mfrs with a good reputation behind them.
ecoharmony.co.uk sell Viridian & other excellent kit parts. Avoid any RCBO with "Rolec" brand stamped on it, in green or blue, these go cheap on eBay, sadly. Deserve to be binned.
More info here! (if you can face it, after that brain-dump!!
Podpoint repair thread here...
Upgrading Rolec with latest PEN-loss & DC gizmo here...