Is it a non latching switch that you're using then ?
Presuming it is, I guess you have two options: change the switch or change to a latching relay.
I would suggest replacing the switch for a latching, live-switching switch, with a tell-tale light.
A Defender Puma heated seat switch (YUF500150LNF) would be ideal for this, as it's all of the above, and it only costs about a fiver new.
It fits in a td5 centre console and you should be able to swap the switch cap over to keep your logo/legend if you wanted to.