Email or call the UK CAA
[email protected]
+44 1293 573700
The reason I say this is because say someone on here says you can do it and it turns out that you can't then you've wasted a lot of time and money. On the flip side if someone says you can't when actually you can, then again maybe you'll waste a lot of time and money doing it somewhere else.
Easiest and correct thing to do is get the answer from the horses mouth. I use to work at the CAA myself and I can't remember the answer to yor question. My gut says you can't, after all a successful LST/LPC goes down as PIC/us in your logbook, and how are you able to be PIC on an aircraft you actually aren't allowed to be Pic on with a JAR licence. Again I can't remember the official answer, and even if I could it wouldn't be official!
Make a phone call/email, easiest way to avoid making a mistake.