I've just signed up to this site to thank everyone that posted/replied on this thread and the one that Leccy758 suggested right at the top.
I've had a Hotpoint Ultima WT741 since 2008. For the past few months, every single light has been flashing on the front, including the time/spin speed display. (The machine still worked, though it would sometimes take an age of holding/constantly pressing the start button for a cycle to start. It was impossible to implement settings like half load or the delay.) Yesterday, I was ready to give in and either purchase a reconditioned machine off gumtree or buy a new one, when as a last resort I stumbled across this thread. I am so glad that I did!
After some initial confusion of taking apart various bits of the washing machine, I found the correct location for the circuit board. From the back of the machine, it is in the bottom left. Remove the plastic cover that goes across the lower part of the back of the machine. Then there is a screw on the left of the machine holding the plastic casing of the circuit board in place. With quite a bit of maneuvering, I managed to get the board out of the back of the machine without disconnecting any of the wires. I removed the plastic casing and located C17 on the board. The capacitor looked slightly domed at the top, though I wouldn't have noticed it if I had not known to look for it.
A trip to a local hardware store for a soldering iron and solder (£12) and then to maplin for a 1000uf 25v capacitor (58p), and then I was back. I haven't soldered in over 15 years since tech classes at school. It was easy enough to remove the existing capacitor. I then needed my girlfriend to hold the new capacitor in place whilst i soldered it in. Amazingly, it worked first time, no more flashing lights, one washing machine working as new, and one proud girlfriend
I guess that the point of this massive post, apart from the enthusiastic "thank you!!" is to say that even for an un-confident novice such as myself, this was a simple enough fix, and hopefully it will give anyone else the confidence to attempt the same!