No court would rule in your favour unless you could show that your ex had failed to respond to a formal written demand for the return of the items. Also, if you intend to claim for the cost of replacements it's essential that you quote accurate figures and can cite your sources (e.g. get hold of a copy of the latest Argos catalogue, use the figures from that and keep a record of the page numbers and item numbers that you've referred to).
Your formal written demand should take the form of a letter sent by recorded delivery (even if your ex lives next door). Obviously you need to keep a copy of it. The letter must clearly show your name and address, your ex's name and address and the date. It should read roughly as follows:
"TAKE NOTICE that I demand the return of my property, as detailed in the Schedule below. Further TAKE NOTICE that if you fail to return any or all of the items listed in the said Schedule within 14 days of this letter, I will commence legal proceedings to recover the cost of replacing any items that have not been returned.
Schedule:
1. Philips DVD player. (Cost of replacement �49.99)
2. Lexmark multi-function printer. (Cost of replacement �78.29)
3. Black & Decker Cordless Power Drill. (Cost of replacement �29.99)
. . .
etc . . . "
If you don't get your property back, start here:
http://www.hmcourts-service.gov.uk/infoabout/c laims/index.htm
Chris