Also, depending upon where you're travelling to, and whether you have an unlocked smartphone available, it might be worth buying a prepay SIM for that country, or stick £10-£20 on a GiffGaff SIM - the EU data roaming charges at least aren't too bad nowadays.
Most phone running apps will still work without a data connection as the actual tracking relies on the GPS chip not the cellular data. Expect to lose some features that rely on the data connection like maps and live web-based tracking, but expect the app to work for time, distance, pace and recording co-ordinates that you will be able to see on a map once you do eventually get back to wifi or home to a data connection.
I assume you've had a recovery week since Bournemouth with mostly rest days and maybe a few easy pace runs?
Jumping straight back into a marathon training plan (especially part way through one) does increase your risk of exhaustion and injury. If you feel that your last plan worked, then the simple rule of thumb back into a schedule is to start with a reverse taper, eg if you had a 3 week taper for Bournemouth, then mirror the weekly volume and quality of those final 3 weeks over the next 3 weeks in order to ease you back in gradually. Then with the remaining 7 weeks until Portsmouth you could pick the final 7 weeks from a marathon training plan - whether the same one as before, or another if you want to try something different.
Hal Higdon plans work for me, that site has a more detailed guide for getting back into training after a marathon:
When I did this race, there was a marshal at the entrance to the underpass calling out "left at the end", but I don't recall seeing a left turn sign at the end of the tunnel - if there was then I missed it. The field was pretty strung out by that point and the closest runner in front of me was already long gone by the time I entered the tunnel, so if I had not heard the marshal then I would have wasted valuable seconds on the other side thinking about which way to go.
Looking at the Google Street View it seems pretty damn obvious that you should turn left and go up the exit ramp and not right up the steps, but after 24 miles it didn't seem so obvious to me, so be warned!
In case an example around similar times helps: After a year of regular running - mainly 5 to 10K, building up to 4 runs and 20-30 miles per week - I managed a 1:28 for my first half marathon when McMillan would have predicted a 1:25 off of my 5K time.
That was with 3 or 4 long runs of 12-14 miles during the couple of months beforehand. So my legs had some familiarity with the distance, but I was still very much undertrained for racing the distance well.
If my 5K had only predicted me a 1:30 at that time I suspect I'd have ended up with about 1:34.
Or if my long runs had all been a few miles shorter then I suspect I'd have ended up with about 1:34, or injury.
Or if both of the above then I suspect I'd have been looking at about 1:40.