Motorhome seats - additional support

i have an ongoing back issue (thousands of golf balls hit on the practice ground over the past 55 years) but i find our Aguti captain's chairs superp for driving, giving great support...no problem driving for hours.

however, in the same chair swivelled, the 'pose' is not the same....upright and focussed ahead...its more reclined and relaxed and this is where i do need some support in the lower back area.

i have managed with a single cushion pressed low into the seat which seems to give a bit of help in just the right area...

When we had M/Cs ,i found that the seats gave less " back stress" when the tyre pressures were less that the 70psi that was the max pressure the base vehicle showed on the door pillar,not many M/Cs need that tyres at that high pressure,

There was also an option on the Fiat base vehicle of a sprung seat frame ,not sure if it is still available,

I have also tried the "back friend" with little success

Lower tyre pressure was the most "successful"

I don't think any two sufferers will have the same issues so recommendations won't count for much.

I've had back problems for 50 years and find the cab seats to be fine. It's squishy furniture that does for me.

Your position behind the wheel can make a world of difference ....

https://www.youtube.com/results?search_query=seating+position+in+car

Tend to agree TW. It's squishy furniture that I find most problem with. The seats in our MH I find very firm and comfortable both in driving and seating modes. However, as MM says positioning for driving, especially on a long run, is very important. Just a shame the seats don't have a memory, or at least electric motors like the X Trail. The optimum position always seems to be between clunks.😂

Driving is fine. It is the leisure positioning that is difficult to get quite right. I found it was mostly the leg position with the seat too high for serious lounging. I've made a small raised step for the area under the table which has the benefit of being a spot to store shoes underneath. 

me too, which is why i could never have the type of lounge that has low backed (no support) seating which is a requirement when turning it into a bed.

IMHO, neither comfortable as a bed nor a seat without mods in both modes.

i can get pretty comfy in the cab seat (swivel, seat base and backrest adjustable) with an extra cushion but never on the poor supportive squishy style you and Steve mention. 

CY, our swivelled seats allow us to put our feet up on the side seats...height seems prwtty good for that. works well with position of TV which drops out od a cupboard directly ahead.

Despite the problem with soft furniture, I find the lounge seating as BB described fine. I find the trick is to park one's backside into the corner and stretch out along the bunk. I've done this with every cvan and MH we've ever had. We all have different problems so my solution won't work for all.

As we've both got the same make of van I know the cab seats are pretty good and no problems really. The interior seats are good too, no sagging or squishiness. I don't know what to advise the OP except to spend time tinkering with the adjustments to get some extra lumber support, our seats can do this maybe some others are not so good? Other than that maybe somebody on here will advise about adjustable back rests etc as you requested.

Don’t forget your cab seats are Merc seats, Brue, but I find the Peugeot Captains Chairs are a good match for them.

The hab upholstery is reasonably firm and I’d say with just the right degree of support and comfort for its dual purpose and nothing like the squishy furniture I was thinking of.