Calculating PRS in UK Biobank

Hi,
I want to calculate PRS in UK Biobank with PRSice2. However, the GWAS used a lot of UK biobank participants as control and proxy case. They then ran a PRS on a cohort where the meta-analysis of the summary stats excluding the cohort and replicating it in another cohort. The PRS was comprised of 1800 variants. Of course, it is much less computation to only use 1800 variants than calculating it from scratch on UK Biobank. I was wondering what might be the best approach? Request a version of the summary stats without UK Biobank and calculating from scratch?