Although the end result was a comfortable win for the Saints, the first half was a close-fought affair. That was despite the hosts exerting plenty of early dominance, rewarded not just by Ben Pons' yellow card just two minutes into the game but Noah Cato's excellent try.
Moseley had held out some power close to the line, but when Rhys Oakley and Ben Nutley made 30 metres from a lineout on the Saints' 22 it put the visitors well and truly on the back foot. Cato ultimately sped in, but he had James Wilson to thank for the peach of a pass which put the full back into clear space.
Moseley got on the board six minutes later when Glyn Hughes - at the second attempt - sent a long-range penalty between the sticks. And prompted by Hughes's attacking intent the Championship outfit took the lead just before the half-hour.
Full back Oliver Thomas made the initial break, England Sevens wing Simon Hunt took it up, and while some great defence stopped Neil Mason close to the line, the defenders had all been sucked in by the attack and there was no one to help Wilson prevent a four-man overlap giving a try to centre Anthony Carter.
This spurred Saints into action, who five minutes later were back in front. Myler's perfectly kicked penalty touchfinder put them on the front foot, and when the hosts worked through the phases - Oakley coming agonizingly close for a second time to a score - the overlap was soon in coming, Cato once more the beneficiary.
Myler's conversion made it 14-10 at the break, and not long after the resumption of play Saints had extended the lead. Replacement Luther Burrell had an immediate impact, picking the ball off his bootlaces at pace and breaking the initial line of defence. The attack rolled remorselessly to the line and Martin Roberts darted over from close range.
Moseley hit back almost immediately through full back Oliver Thomas while the Saints coaches started to send the replacements on and blood some youth - Academy prospects Tom Stephenson, Will Hooley, Ryan Glynn and Danny Hobbs all entering the action before the hour.
However it was a youngster who had been on from the start, wing Tom Collins, who grabbed the next score, cutting back in off Oakley's break to sidestep and sprint his way over. And when Burrell powered his way over for the fifth try four minutes later the contest was as good as sealed.
Moseley had the last say with a Ben Pienaar try six minutes from time, but it was too little, too late, and the Saints head north in good spirits for their final pre-season game before the Aviva Premiership Rugby campaign gets underway on September 1st.
2mins MOSE Yellow card Pons
7mins SAINTS Try Cato Con Myler 7-0
11mins MOSE Miss pen Hughes
13mins MOSE Pen Hughes 7-3
27mins MOSE Try Carter Con Hughes 7-10
32mins SAINTS Try Cato Con Myler 14-10
HALF-TIME SAINTS 14 MOSELEY 10
47mins SAINTS Try Roberts Con Myler 21-10
50mins MOSE Try Thomas 21-15
60mins SAINTS Try Collins Con Hooley 28-15
64mins SAINTS Try Burrell Con Hooley 35-15
74mins MOSE Try Pienaar Con Ryan 35-22
FULL-TIME SAINTS 35 MOSELEY 22