Izzie,
Virus tests are expensive.
You can order them from Agdia and for about $125 they will send you 25 test kits that are good for about one year....about $5 per test.
Unfortunately, they will not send smaller quantities.
This is a perfect situation where it is worth it to have a test available.
If you would not have use for 25 tests over the course of one year, I recommend making some friends at your local orchid society and going in together for an order of tests.
Your new absolutely gorgeous plant may have been a bargain at the supermarket and you may think spending another $5 to test it not quite reasonable.
But I look at it this way...the $5 is protection for the REST of your plants.
The tests are easy to run and the biggest tip for running the test is NOT to use too much specimen (read instructions!)
...after you at least test the plant, you can manage it from there with relative confidence. Too me, blooms on a worrisome plant are not as pleasurable.
The older leaves you showed are suspicious and I would test it.