Flashing

(RRP £11.90) £9.98 - £17.74
(RRP £35.29) £12.07 - £39.07
(RRP £14.75) £13.27 - £53.14
(RRP £11.46) £8.60 - £34.25

Flashing tape and the required primers are listed here.  You'll also find patination oil to rejuvenate previously applied lead flashings.