So it turns out they were the right way round. I tried rotating them 180 and they were even worse. So, upon turning them around the original way I inserted the bulb first, then pushed on the electrical connector, as per previously suggested. Huge improvement! Previously by putting the connector on first then pushing into the holder it must not have seated properly.
Also, I can fully recommend the philips xtreme vision +130% bulbs. I've always used philips upgrade bulbs but I've never used the +130% due to the price. But eurocarparts stock them for £20 (still £10 cheaper than most online bulb stockists) and a lot cheaper then when they originally came out.