UPDATE
Just got back last night with a new 90 day Non Imm O.
All went smoothly with just a couple of minor unexpected requests.
Getting there = We parked up in the large covered car park at the bridge (250 THB per night) then went through Immigration and caught the coach (50 THB per person, coaches every hour and a half or so.) Bit of a scrum getting on the coach with loads of cargo piled up on back seats and our seat had a large packed item making it a squeeze. We could have got a hired car at the wee souvenir shop next to the big car park, we decided against it thinking it was not good value (3500 THB) to just take us to our hotel in Savannakhet. But we met a fellow Brit in Lins Cafe (recommended) and he said he does use that same firm and the deal is - they take you through the immi (doing some of the paperwork) and deliver you to the Thai consulate to drop off application then take you to your hotel, then collect you next day - take you to consulate to collect visa then back to the Thai side (i don't know if all that is true but i believe this guy is legit, worth checking this "taxi" firm out to take a fair bit of hassle out of the equation if we need to go back in future). Best to get a number of a tuk tuk driver for getting around town if like us, people get digs a bit out of the centre of town. We used a food delivery called "Foodpanda" which was good - GoTeddy is another option. You will need access to a Laos mobile number for foodpanda (our landlady @ Thongkan Mansion helped us out there).
Visa application went as hoped except we were asked to get a copy of the Khor Ror 22 (the wife chatted with the guy and i think he asked for that because she mentioned it), the Thai consular staff do seem to have a reputation for being very helpful. I've attached a photo of the opening times for the Consulate - We didn't know that applications were only between 0900 - 1100 and collections from 1400 - 1600 next day (we missed it on our day of arrival but did book the digs for a couple of days just in case.
Coming back - Landlady was great, took us to collect visa then to the bridge to get the coach (taxi options there as well but we stuck with the coach). All went well but i was asked to provide C-19 vaccine evidence (which we had anyway because we expected the Laos Immi to ask for it), i didn't expect the Thai Immi to ask for that (maybe it's because i was wandering around with my mask pulled down and not being as diligent as the locals. Would they have asked for it if i was masked up ? who knows.
All the costs for Visas and transportation were as expected.
Good luck.
Jock