I would definitely think about upping your training before Christmas if you are going for sub 4.But if it is your first marathon I would agree with FRC - just go out and enjoy it. The London Marathon is just a fabulous experience as a runner.
Well done Ikle on your Parkrun PB. You are a couple of minutes faster than me at the moment but I am planning on bringing my PB down next year. No Parkruns for me until after Christmas because of Strictly.
Fido you seem to be having rotten luck. I hope the physio works out in the end.
I am planning 10 miles later this afternoon, the longest I have done since the London Marathon. I did 8 miles last weekend and although it felt ok I was very tired after.
Very sorry to hear about your cat FRC. We have two, about 12 years old. They don't come to anyone else in the house except me. They seem well enough at the moment but I do think they will soon be on borrowed time.