To be honest any show involving moving armour (indeed any vehicles) is going to be a 'behind the barrier' deal these days, health & safety and insurance requirements. I'm not sure what interaction you are hoping for, but climbing on tanks is not encouraged much either for the same reasons, though the modern equipment displays at the TM usually permit it, ladders and gantries being provided.
I'm a bit baffled by the prices you quote, the TM website gives £38 per adult for a weekend ticket and £23 per day, the £110 is a premium ticket, which seems a lot (in my opinion) extra for a seat, food and drink and a programme? The premium tickets do not claim to give greater access to the vehicles.
jh