SEO fixes: schema cleanup, duplicate redirects, sitemap, about page

- faq.php: replace deprecated FAQPage with WebPage, remove HowTo schema
- about.php: remove incorrect Dataset schema; add Credentials and
  Founder sections (576 -> 2059 words, E-E-A-T improvement)
- .htaccess: 301 redirects for 3 duplicate article pairs
  (airflow x2, kafka x2, real-time-analytics x2)
- Canonical tags updated on redirected source articles
- sitemap-blog.xml: add 4 missing articles, remove redirect slug (47->50)

sitemap-blog.xml

@@ -181,12 +181,7 @@
     <changefreq>monthly</changefreq>
     <priority>0.7</priority>
   </url>
-  <url>
-    <loc>https://ukdataservices.co.uk/blog/articles/real-time-analytics-streaming</loc>
-    <lastmod>2026-03-08</lastmod>
-    <changefreq>monthly</changefreq>
-    <priority>0.7</priority>
-  </url>
+
   <url>
     <loc>https://ukdataservices.co.uk/blog/articles/real-time-data-extraction-technical-guide-uk-businesses</loc>
     <lastmod>2026-03-08</lastmod>
@@ -286,4 +281,32 @@
         <changefreq>monthly</changefreq>
         <priority>0.7</priority>
     </url>
+
+    <url>
+        <loc>https://ukdataservices.co.uk/blog/articles/data-protection-impact-assessment-web-scraping-uk</loc>
+        <lastmod>2026-03-20</lastmod>
+        <changefreq>weekly</changefreq>
+        <priority>0.7</priority>
+    </url>
+
+    <url>
+        <loc>https://ukdataservices.co.uk/blog/articles/performance-evaluation-apache-kafka-real-time-streaming</loc>
+        <lastmod>2026-03-20</lastmod>
+        <changefreq>weekly</changefreq>
+        <priority>0.7</priority>
+    </url>
+
+    <url>
+        <loc>https://ukdataservices.co.uk/blog/articles/python-airflow-alternatives</loc>
+        <lastmod>2026-03-20</lastmod>
+        <changefreq>weekly</changefreq>
+        <priority>0.7</priority>
+    </url>
+
+    <url>
+        <loc>https://ukdataservices.co.uk/blog/articles/what-is-real-time-data-streaming</loc>
+        <lastmod>2026-03-20</lastmod>
+        <changefreq>weekly</changefreq>
+        <priority>0.7</priority>
+    </url>
 </urlset>