Pagination for this type of site

Hello, I can collect the data from the spreadsheet of this site, however, I cannot progress in the pagination for the other letters. can anybody help me? Thank you!

Url: http://greyhoundstats.co.uk/graded_greyhound_stats.php

Sitemap:
{"_id":"galgos-stats","startUrl":["http://greyhoundstats.co.uk/graded_greyhound_stats.php"],"selectors":[{"id":"elements","type":"SelectorElement","parentSelectors":["_root"],"selector":"tr:nth-of-type(n+2)","multiple":true,"delay":0},{"id":"dog","type":"SelectorText","parentSelectors":["elements"],"selector":"td[align='left']","multiple":false,"regex":"","delay":0},{"id":"runs","type":"SelectorText","parentSelectors":["elements"],"selector":"td:nth-of-type(2)","multiple":false,"regex":"","delay":0},{"id":"wins","type":"SelectorText","parentSelectors":["elements"],"selector":"td:nth-of-type(3)","multiple":false,"regex":"","delay":0},{"id":"strike-rate","type":"SelectorText","parentSelectors":["elements"],"selector":"td:nth-of-type(4)","multiple":false,"regex":"","delay":0},{"id":"seq-reds","type":"SelectorText","parentSelectors":["elements"],"selector":"td:nth-of-type(7)","multiple":false,"regex":"","delay":0},{"id":"last-run","type":"SelectorText","parentSelectors":["elements"],"selector":"td:nth-of-type(8)","multiple":false,"regex":"","delay":0}]}