hiya Neil. I have the 300d with kit lens and got the housing, 5503 dome, TTL syc cord and manual controller from
www.uwcp.com in the states. Ryan is a great help there. Total cost was $1375 (about £833). Add to this £127 for import/VAT totalled £960. At the time, UK costs would have been about £1200
If you want any more info, pm me. I assume you will also need a strobe - I would recommend the DS125 or the INON (I have the DS125). I got this from BHphotovideo in the states - also saved about £200 on the deal)