Starter relay or no starter relay, Been reading up for an hour and still don't know!! Options

[David Stowers]

On two occasions recently on pulling onto my driveway after a long journey my car won't restart after turning off to unlock the garage door. Luckily I can then just push the car in but with a European tour booked in the summer I'd like to sort the problem.
When I get back in after opening the garage the lights on the dash dim when I turn the key to start but there is no click. 20 minutes later it will start right up. Is this the problem that will be solved by a hot start relay kit or just a good old fashioned sticky solenoid? I'd rather do just the relay or just replace the solenoid so which is it?
Thanks guys

[Tom]

Actually the normal state of the relay is open, and when power is applied, it closes.
Minor point, but could confuse some new person.
I spent a good deal of time thinking about the diode remedy to suppress the inductive spike from the solenoid. I do believe the correct size diode would work, however, how would one know it is still working a week/month/year later? You wouldn't, until suddenly you have a start issue and find out during troubleshooting that the problem was the diode had failed. With the relay, if it fails, you know right away. So I think the relay remedy is the best all around fix in this case.
There are many different relays that will do the job. For whatever it is worth, I prefer one of the Bosch style as it requires no tools to replace one in an emergency. Just unplug the spade lugs from the old one and plug them into the new one. 2 minutes and a zip tie and you're back on the road. You can finish the installation when you get home.
Tom