Sorry to jump on an old post but I was searching for chassis / bulkhead info
I bought a marsland chassis for Kdlandrovers a few weeks ago they work are in partnership with marsland and do all the retail for them you just order through them (the lady at marsland gave me the contact details for them and explained how it works. they sell them at the marsland direct price to), this was really helpful for me as I wasn't sure to go with a steel or plastic tank, they advised me and as thy work direct with marsland I was able to order exactly what I wanted. the delivery time was only 2 weeks from ordering and included delivery just wish they did bulkheads to!