They opened the pressure bungs when doing it, in fact I seem to remember the tanker conversion wiring was done at Bournemouth and Hunting at East Mids offered to run the wiring and coil it through the bulkheads while they had them apart so it didn’t need to be done again thus saving both time and money, but it was turned down as it was a different contract. The last Ten to leave East Mids lost some U/C bay panels on departure to much embarrament.