David,
I'm only mentioning this to save you from possible

These are quotes from last October's issue of MEW:
"UK subscribers can find their subscriber number on the grey envelope that their magazine arrived in. I will pause for a moment while you all rush out to the rubbish bin..... now I bet you wish you had not destroyed the envelope"That's true in my case. I had to wait another month
"UK subscriber numbers are in the format 00********R MEW156. Just enter the 8 digit code where the *s are. Ignore the first two 00s and everything after the last *."It goes on to say that (in the UK at least) only direct subscriptions to Magicalia or MyHobbyStore or whatever it's calling itself this week will suffice. An order placed with your local magazine vendor won't count.
I'm not sure what the arrangements will be for subscribers outside the UK, but no doubt there will be similar hoops to jump through.
As has already been said, a subscription to the paper copy only gets you access to digital archive of magazines for for the last 3 years or so. To go back earlier (to Issue 1 of MEW; I'm not sure about Model Engineer) you have to fork out more money - I think it's £29, and that this only buys access during the forthcoming year. after that, you have to pay again.
Andy