matey - I am 90% ES intraday trader. with ES u shoot for anything from 15 min to several hours.
UK techs r my old passion. I traded options (mostly OTC) on UK techs as a pro (Geo Interactive, Autonomy, Bookham, Mysis, Sage etc.) - and i just love this good old Great British illiquid tech world - illiquid by comparison to US techs. With options on UK techs if it goes against u - u just hv NO chance to stop yrself out - too illiquid - unlike US techs where u go to listed mrkt - take a loss - but u KNOW what exact loss u'll take.... 🙂
anyway answering yr Q - I dont daytrade UK Techs - go for swings, couple of days maybe longer sort of thing.
Very good observation about ARM btw. Well spotted. I was working 119 back then, didnt get a fill, but got filled later on when the Old Lady was closed on ADRs at 6.50 USD. Of coz next morning I cud get 119 on LSE 🙂 but anyway was a nice 10% win over the couse of just a few days.
With reuters e.g. got filled on exactly what u mentioned - this early morning dip to 395. comfortably closed right after 10:30 that day at 415.50 pp. But i agree this time round it probably neds to retrace more.