I went to Stratco to change over a gas bottle. $34.95, um no thanks. Bunnings do it for $23.95, can you match? OK no probs. They don't care about the date on the bottle either. Last week I was at Colli & Sons Hardware in Malaga, $22 swap and go for 8.5kg.
I used to be "bottle sensitive" and kept getting mine refilled. Then it became harder, less convenient and no difference in price. Now I just go for a bottle minimum 2 years in date. They all seem to fit my camper trailer bottleholder.