I have also bought designer frames online and had my prescriptions glass put in them, but the cost was round £400.00. I admit I have nevered used spec-savers because I do not like their frames.
I use Duncan and Todd. The sunglasses I bought in Calis were £220.00 for varifocal and I thought that was cheap. I have never heard of varifocals being as cheap as £70.00 for frames and varifocals. However, let me have the details, because, when I get back to the U.K. I have to pick up a new pair of glasses, so I will show you post the Optician. Also right next door to Duncan and Todd is Specsavers. I will check them out too, because if I can send for designer frames and get them to fit varifocals for £70.00 I think I buy quite a few more pairs.