Suzy,
I've used the
Siebert e/p's with great success for 4 years.
They are made in 1 1/4" and 2" barrel sizes.
You buy them direct from the manufacturer in the U.S
They don't have a 5mm, but do have a 7mm.
With postage it should bring it in to around $200.
They have 20mm eye relief and a 70* A.field of view.