Across:
1. 1962 hit for Elvis Presley: Return to ______ (6)
5. Capital city of Jordan (5)
7. Birthplace of Albert Einstein (3)
8. Member of the Royal Military Police (6)
9. Major US retailer, Home _____ (5)
12. Capital city of the Seychelles (8)
14. Fluid within a plant (3)
15. Stage name of O'Shea Jackson Sr. (3,4)
16. Person held in servitude to repay a debt (4)
17. Seven-time Grammy award-winner, ______ Estefan (6)
21. 'In _____', before birth (5)
23. Strong forward flow (6)
25. Hairdressing establishment (5)
26. Legendary King of Pylos (6)
29. Give up (4)
31. Landscape (7)
33. Female reproductive cells (3)
34. Stick out further than something at a lower level (8)
36. Racecourse six miles south of Windsor Castle (5)
38. Taste and enjoy to the full (6)
40. Female sheep (3)
41. 1990's US drama series, Dr _____, Medicine Woman (5)
42. John ______, inventor of the pneumatic tyre (6)
Down:
2. Organ of sight (3)
3. Gold coin formerly used as currency in Europe (5)
4. Scarf-wearing British children's comic strip character (6,4)
5. Theatre performed by non-professionals (2-4)
6. Shakespeare play, Much ___ About Nothing (3)
8. Increasing the running speed of an engine (7)
10. Microsoft Windows command, Ctrl+V (5)
11. Gain access to (a resource) (3,4)
13. Guiding belief or principle (5)
16. 'Cross _____', encounter someone or something (5)
18. ___ Michele, Glee actress (3)
19. 'Rule the _____', be in complete control (5)
20. Pub (3)
21. Take advantage of (3)
22. Winnie the Pooh character (3)
24. Not yet published (10)
25. Genus of redwood coniferous trees (7)
27. Jewelled head ornament (5)
28. One who goes back on a promise (7)
30. _____ Newton, English mathematician (5)
32. Become less hard (6)
35. Place of safety (5)
37. Former French coin of low value (3)
39. Card game (3)
Also, what is the significance of the answers highlighted in yellow?