[[!+nowdate:default=`now`:strtotime:date=`%c`]]
This question has been answered by BobRay. See the first response.
date.timezone = "Europe/London"
Try setting the date_timezone System Setting to "Europe/London" (without the quotes).
If that doesn't do it, try adding this line to a php.ini file in the MODX root (create one if necessary):
date.timezone = "Europe/London"
If that doesn't work, check the Date section of PhpInfo() (Manage -> Reports -> System Information -> phpinfo() link) to see what time PHP thinks it is.
Sorry, I mis-wrote. I meant what timezone PHP thinks it is, not what time.
Glad you got it sorted.