So here are some thoughts on how you might get what you want, without needing an IVA.
And I'd like to stay in the S2 "school". Sensibly, that means not much under an 88" wheel-base.
OK, so the starting vehicle is a pre-1969 lights-in-grille S2a Bitsa. Might as well use a Bitsa if you are going to cut it about. Something with a legitimate identity and either a decent chassis and bulkhead or getting them fitted as part of the process.
I'd want to fit "reverse" seat belts .... buckling below drivers right hip, not in middle of cab.
Steel conduit inside the chassis rails, with wiring wrapped in spiral binding.
Rock sliders,
Exterior mirrors hung on shorty roof rack.
Second 7- pin socket mounted on front. Both 7 and 13-pin sockets mounted on rear. & 7-pin socket mounted in cab. Work lamp to plug into any of the 7-pin sockets.
Aim for 500kg (unbraked) and 1000kg braked, towing capacity.
Can't see anything there which would cause any issues - these are things you could just go ahead and do if you want to any vehicle. You already have more than that towing capacity.
Pair of "dip-left central head lamps, for UK driving, with a pair of "dip-right" spot lamps in front of the wings, for continental driving (might need to be "dip-left" for the SVA).
Something to this effect could be achieved by installing post-1969 wings complete with lights and either setting it up with independent switches or, probably better, fitting an 'A or B' type switch to select between them. I don't know if this is legal, but I have seen it done to other vehicles and both were legal options at the time of construction of the vehicle, so it may be acceptable without constituting a change which requires any form of vehicle assessment.
I also want the seat cushions to be the same height as our mutual inside legs (29.5").More impure thoughts about how to lower the cushions.
Spare wheel on bonnet, with a pair of "snow tyres" in the tub.
This is where it gets trickier. What is the current height of the seat cushion? Assuming you need to lower it, you need to consider the following:
1. Does it need to drop below the height of the seat box? If so, you would need to fabricate a new top. This may be straight across or may be only on the sides, depending on whether you are going low enough to hit gearbox components. Hypothetically, it may be possible to make the seatboard slide in and out so you just sit down on it, press the button and it slides you in to the vehicle. There are things a bit like this in some adapted vehicles.
2. If the seat is lower, do you need the floor to be lower too? A custom sill rail could be fabricated to achieve this - there are no outriggers in the way. You would also need to marry up to the front of the seatbox (easy) and the bulkhead (trickier to get right). On an earlier vehicle the sill covers are 5" deep so dropping that far would not take you outside the existing bodywork envelope.
3. How do you deal with moving the foot controls? They could be slid down the bulkhead panel but that moves them further away from the seating position. You could move the seat forward to address this but the compartment would then be smaller so shuffling yourself in would get more difficult. The brake and clutch have hose connections so moving them has no impact on their performance. The accelerator pedal has a rod linkage as standard, but some carburettor options require installing a bowden cable anyway which would make that independent of position.
4. How tiring does it get using the steering wheel that much higher up? It is difficult to lower the wheel as it uses simple mechanical linkages, however if you go for a suitable power steering option you would be more flexible on positioning.
None of the above appears to be particularly radical alteration. You are remaining within the envelope of the vehicle and you are not modifying any of the components which relate to safety of either yourself or other road users. As such, I would be interested to know whether you would actually need an IVA to achieve it - on the face of it, it looks like you may not, in which case you could just go ahead and do it, retaining the original identify of the vehicle. You are retaining the original (or type) chassis, engine, transmission, axles and suspension so the only two points you may lose are for the steering.
One thing though, I don't think you would get away with leaving the wheel on the bonnet if you lower the seat. You simply won't see over it!
Alec
