Alan is correct. It's a Strathearn SP100 from the last couple of years of their paperweight production.
See
this page in Richard More's website for another, particularly good, signed and dated example (but I would say that - it's one of my weights!). Others in the SP1xx range within Richard's site show that there could have been a really good future for millefiori weights from Strathearn if the management had recognised the collector potential of those "experimental" items.
And yes, to some extent, there is a similarity to some Ysart items (both Paul's work and from his father and brothers), especially with the SP100 concentrics. But in truth, these later Strathearn weights are simply very well made pieces that, in my mind, are every bit as good as many antique French examples, not just good Ysart pieces.