Add spaces: TheleadersoftheinvaderswereHengistandHorst.

Answer: The leaders of the invaders were Hengist and Horst.

Add spaces: PDFjustonetoolforthemostcommoncrimpingapplications

Answer: PDF just one tool for the most common crimping applications

Add spaces: IthassimilaritieswithEtonFives,anothertypeofFives.Thegameisplayedassinglesordoubles,theaimbeingtohittheballabovea"bar"acrossthefrontwallinsuchawayastheoppositioncannotreturnitbeforeasecondbounce.

Answer:
It has similarities with Eton Fives, another type of Fives. The game is played as singles or doubles, the aim being to hit the ball above a "bar" across the front wall in such a way as the opposition cannot return it before a second bounce.