You can get 5 rolls of Portra 800 in 120 format, for £31.99 inc P&P from a well known source in Jersey.
My personal preference would be to pay that extra 40p per for roll for a top-rank Kodak product.
Alternatively, pay less for Portra 400 (£20.99 for five rolls) and uprate it to 800, as it has a wide exposure latitude. I have a few rolls of 35mm Fuji Pro 800z in the freezer, and I liked it a lot before I tried the new Portra, but now it's hard to find the motivation to use it.
If the Lomo film is made by Fuji, it could be based on Superia 800 rather than Pro 800Z